Skip to content

Schema Reference

This page provides a reference for all the capability data models and types used within the UCP.

Capability Schemas

Location Lookup

Location lookup by identifiers. Supports batch retrieval and single-location detail.


Location search capability. Supports natural language queries, distance and serviceability relations, structured filtering including current item availability, and pagination.


Cart

Name Type Requirement Description
ucp any Required; omitted in requests UCP metadata for cart responses. No payment handlers needed pre-checkout.
id string Required; omitted in requests Unique cart identifier.
line_items Array[Line Item] Required Cart line items. Same structure as checkout. Full replacement on update.
context Context Optional Buyer signals for localization (country, region, postal_code). Merchant uses for pricing, availability, currency. Falls back to geo-IP if omitted.
signals Signals Optional Environment data provided by the platform to support authorization and abuse prevention. Values MUST NOT be buyer-asserted claims — platforms provide signals based on direct observation or independently verifiable third-party attestations. All signal keys MUST use reverse-domain naming to ensure provenance and prevent collisions when multiple extensions contribute to the shared namespace.
attribution Attribution Optional Platform-emitted referral and conversion-event context — campaign identifiers, click IDs, source/medium markers, etc. The same parameters platforms communicate via URL query parameters in browser-based flows.
buyer Buyer Optional Optional buyer information for personalized estimates.
currency string Required; omitted in requests ISO 4217 currency code. Determined by merchant based on context or geo-IP.
totals Totals Required; omitted in requests Estimated cost breakdown. May be partial if shipping/tax not yet calculable.
actions Actions Optional; omitted in requests Outstanding extension-defined Actions for this cart.
messages Array[Message] Optional; omitted in requests Validation messages, warnings, or informational notices.
links Array[Link] Optional; omitted in requests Optional merchant links (policies, FAQs).
policies Array[Policy] Optional; omitted in requests Policies (e.g., return/refund terms) that apply to the items in this cart. applies_to targets are relative to the response root; when absent or empty, refer to the URLs in links[].
continue_url string Optional; omitted in requests URL for cart handoff and session recovery. Enables sharing and human-in-the-loop flows.
expires_at string Optional; omitted in requests Cart expiry timestamp (RFC 3339). Optional.

Catalog Lookup

Product/variant lookup by identifier. Supports batch retrieval (lookup_catalog) and single-product detail (get_product).


Product catalog search capability.


Checkout

Name Type Requirement Description
ucp any Required; omitted in requests UCP metadata for checkout responses.
id string Required; omitted in requests Unique identifier of the checkout session.
line_items Array[Line Item] Required; omitted on complete List of line items being checked out.
buyer Buyer Optional; omitted on complete Representation of the buyer.
context Context Optional; omitted on complete Provisional buyer signals for relevance and localization—not authoritative data. Businesses SHOULD use these values when verified inputs (e.g., shipping address) are absent, and MAY ignore or down-rank them if inconsistent with higher-confidence signals (authenticated account, risk detection) or regulatory constraints (export controls). Eligibility and policy enforcement MUST occur at checkout time using binding transaction data. Context SHOULD be non-identifying and can be disclosed progressively—coarse signals early, finer resolution as the session progresses. Higher-resolution data (shipping address, billing address) supersedes context.
signals Signals Optional Environment data provided by the platform to support authorization and abuse prevention. Values MUST NOT be buyer-asserted claims — platforms provide signals based on direct observation or independently verifiable third-party attestations. All signal keys MUST use reverse-domain naming to ensure provenance and prevent collisions when multiple extensions contribute to the shared namespace.
attribution Attribution Optional Platform-emitted referral and conversion-event context — campaign identifiers, click IDs, source/medium markers, etc. The same parameters platforms communicate via URL query parameters in browser-based flows.
status string Required; omitted in requests Checkout state indicating the current phase and required processing. See Checkout Status lifecycle documentation for state transition details.
Enum: incomplete, requires_escalation, ready_for_complete, complete_in_progress, completed, canceled
currency string Required; omitted in requests ISO 4217 currency code reflecting the merchant's market determination. Derived from address, context, and geo IP—buyers provide signals, merchants determine currency.
totals Totals Required; omitted in requests Different cart totals.
actions Actions Optional; omitted in requests Outstanding extension-defined Actions for this checkout.
messages Array[Message] Optional; omitted in requests List of messages with error and info about the checkout session state.
links Array[Link] Required; omitted in requests Links to be displayed by the platform (Privacy Policy, TOS). Mandatory for legal compliance.
policies Array[Policy] Optional; omitted in requests Policies (e.g., return/refund terms) that apply to the items in this checkout. applies_to targets are relative to the response root; when absent or empty, refer to the URLs in links[].
expires_at string Optional; omitted in requests RFC 3339 expiry timestamp. Default TTL is 6 hours from creation if not sent.
continue_url string Optional; omitted in requests URL for checkout handoff and session recovery. MUST be provided when status is requires_escalation. See specification for format and availability requirements.
payment Payment Optional; required on complete Payment configuration containing handlers.
order Order Confirmation Optional; omitted in requests Details about an order created for this checkout session.

Order

Name Type Requirement Description
ucp any Required UCP metadata for order responses. No payment handlers needed post-purchase.
id string Required Unique order identifier.
label string Optional Human-readable label for identifying the order. MUST only be provided by the business.
checkout_id string Required Associated checkout ID for reconciliation.
permalink_url string Required Permalink to access the order on merchant site.
line_items Array[Order Line Item] Required Line items representing what was purchased — can change post-order via edits or exchanges.
fulfillment object Required Fulfillment data: buyer expectations and what actually happened.
adjustments Array[Adjustment] Optional Post-order events (refunds, returns, credits, disputes, cancellations, etc.) that exist independently of fulfillment.
currency string Required; omitted in requests ISO 4217 currency code. MUST match the currency from the originating checkout session.
totals Totals Required Different totals for the order.
policies Array[Policy] Optional; omitted in requests Snapshot of the policies that applied to the items at checkout, captured on the order as a durable record. applies_to targets are relative to the response root.
messages Array[Message] Optional Business outcome messages (errors, warnings, informational). Present when the business needs to communicate status or issues to the platform.
attribution Attribution Optional; omitted in requests Snapshot of the attribution associated with the originating checkout. Read-only on the order.

Type Schemas

Actions

Outstanding extension-defined Action instances, keyed by reverse-domain Action type, not extension name.


Amenity Type

Name Type Requirement Description
Reverse-domain identifier used for collision-safe namespacing of capabilities, services, handlers, eligibility claims, and extension-contributed keys. Must contain at least two dot-separated segments (e.g., 'dev.ucp.shopping.checkout', 'com.example.loyalty_gold'). Segments after the first are domain- or identifier-derived: they may contain interior hyphens, may start with a digit, and may contain underscores (e.g., 'com.example-shop.checkout', 'com.2example.cart', 'dev.ucp.common.identity_linking'), but must not start or end with a hyphen. The first segment (the reversed top-level domain) is letters and digits, and may contain interior hyphens to support internationalized (punycode) top-level domains such as 'xn--p1ai'.

Pattern: ^[a-z](?:[a-z0-9-]*[a-z0-9])?(?:\.[a-z0-9](?:[a-z0-9_-]*[a-z0-9_])?)+$


Amount

Monetary amount in the currency's minor unit as defined by ISO 4217. Refer to the currency's exponent to determine minor-to-major ratio (e.g., 2 for USD, 0 for JPY, 3 for KWD).


Available Payment Instrument

Name Type Requirement Description
type string Required The instrument type identifier (e.g., 'card', 'gift_card'). References an instrument schema's type constant.
constraints Constraint Expression Optional A Constraint Expression describing the instrument this entry makes available. Keys in properties name members of the constraint_target declared by the instrument schema for this type. Requirements on submitted request data belong in ucp.request_constraints instead.

Binding

Name Type Requirement Description
type Reverse Domain Name Required The capability that owns the bound resource, for example dev.ucp.shopping.checkout. MUST be a capability name declared in the UCP namespace.
id string Required Opaque identifier of the bound resource within the owning capability, for example a checkout identifier.

Business Split Payments Config

Name Type Requirement Description
allowed_combinations Array[array] Required Array of valid instrument combinations. Each combination is an array of instrument groups. A payment is valid if it matches any combination.

Card Credential

Name Type Requirement Description
type string Required The credential type discriminator. Specific schemas will constrain this to a constant value.
type any Required Constant = card. The credential type identifier for card credentials.
card_number_type string Required Deprecated: the credential type now carries this distinction. The type of card number. Network tokens are preferred with fallback to FPAN. See PCI Scope for more details.
Enum: fpan, network_token, dpan
number string Optional Card number.
expiry_month integer Optional The month of the card's expiration date (1-12).
expiry_year integer Optional The year of the card's expiration date.
name string Optional Cardholder name.
cvc string Optional Card CVC number.
cryptogram string Optional Cryptogram provided with network tokens.
eci_value string Optional Electronic Commerce Indicator / Security Level Indicator provided with network tokens.

Card Payment Instrument

Name Type Requirement Description
id string Required A unique identifier for this instrument instance. Typically assigned by the platform for instruments it collects. For a business-owned saved instrument returned on an identity-linked response, this identifier is assigned by the business; the platform MUST treat it as an opaque, business-scoped reference, and the business resolves it server-side when the buyer selects it.
handler_id string Required The unique identifier for the handler instance that produced this instrument. This corresponds to the 'id' field in the Payment Handler definition.
type string Required The broad category of the instrument (e.g., 'card', 'tokenized_card'). Specific schemas will constrain this to a constant value.
billing_address Postal Address Optional The billing address associated with this payment method.
credential Payment Credential Optional The base definition for any payment credential. Handlers define specific credential types.
display object Optional Display information for this payment instrument. Each payment instrument schema defines its specific display properties, as outlined by the payment handler.
type string Required Constant = card. Indicates this is a card payment instrument.
network string Optional Card network elected for this transaction, typically a co-badged selection. When present, the business MAY decline if the card cannot route over it and MUST NOT substitute another.
display object Optional Display information for this card payment instrument.

Constraint Expression

Name Type Requirement Description
required Array[string] Optional Property names required by the constrained object. Must be non-empty: an empty array applies no constraint.
properties object Optional Constraints keyed by property name. Must be non-empty: an empty object applies no constraint.
anyOf Array[Constraint Expression] Optional Alternative Object Constraints. The constrained object must satisfy at least one. A branch must be non-empty: an empty branch is satisfied by every object and neutralizes the alternation.

Context

Name Type Requirement Description
address_country string Optional The country, as a 2-letter ISO 3166-1 alpha-2 code (e.g. "US"). A 3-letter alpha-3 code or full country name MAY also be used.
address_region string Optional The first-level administrative region within the country (e.g. a state or province such as California).
postal_code string Optional The postal code (e.g. "94043").
location string Optional Stable, opaque identifier for a Location in the Business's namespace. This provisional, non-binding hint is distinct from the Buyer's locality. The operation specification or an active capability/extension defines its effects. A common example in retail shopping is the default home store ID selected and saved by the user when purchasing groceries.
intent string Optional Background context describing buyer's intent (e.g., 'looking for a gift under $50', 'need something durable for outdoor use'). Informs relevance, recommendations, and personalization.
language string Optional Preferred language for content. Use IETF BCP 47 language tags (e.g., 'en', 'fr-CA', 'zh-Hans'). For REST, equivalent to Accept-Language header—platforms SHOULD fall back to Accept-Language when this field is absent; when provided, overrides Accept-Language. Businesses MAY return content in a different language if unavailable.
currency string Optional Preferred currency (ISO 4217, e.g., 'EUR', 'USD'). Businesses determine presentment currency from context and authoritative signals; this hint MAY inform selection in multi-currency markets. Also serves as the denomination for price filter values — platforms SHOULD include this field when sending price filters. Response prices include explicit currency confirming the resolution.
eligibility Array[Reverse Domain Name] Optional Buyer claims about eligible benefits such as loyalty membership, payment instrument perks, and similar. Recognized claims MAY inform the Business response (e.g., member-only product availability, adjusted pricing in catalog, provisional discounts at cart or checkout). Businesses MUST ignore unrecognized values without error. Values MUST use reverse-domain naming (e.g., 'com.example.loyalty_gold', 'org.school.student') and MUST be non-identifying.
payment Array[object] Optional Buyer-preferred payment handlers in priority order (most preferred first). Each entry names a handler advertised in the Business profile's ucp.payment_handlers, optionally narrowed to preferred instrument types. The Business SHOULD use it to preselect or prioritize the handler (and type, when given) and MAY ignore unavailable or ineligible entries; unrecognized values MUST be ignored without error.

Daily Hour

Name Type Requirement Description
opens string Required; omitted in requests Opening time in 24-hour HH:MM format.
closes string Required; omitted in requests Closing time in 24-hour HH:MM format.
day string Required; omitted in requests A stable UCP day-of-week identifier for the day on which this recurring local civil-time interval begins in the containing Location's timezone. It is not localized display text.
Enum: monday, tuesday, wednesday, thursday, friday, saturday, sunday

Description

Name Type Requirement Description
plain string Optional Plain text content.
html string Optional HTML-formatted content. Security: Platforms MUST sanitize before rendering—strip scripts, event handlers, and untrusted elements. Treat all rich text as untrusted input.
markdown string Optional Markdown-formatted content.

Error Code

Error code identifying the type of error. Standard errors are defined in capability specifications (see examples) and have standardized semantics; freeform codes are permitted.


Error Response

Name Type Requirement Description
ucp any Required UCP protocol metadata. Status MUST be 'error' for error response.
messages Array[Message] Required Array of messages describing why the operation failed.
continue_url string Optional URL for buyer handoff or session recovery.

Exception Hour

Name Type Requirement Description
opens string Optional; omitted in requests Opening time in 24-hour HH:MM format.
closes string Optional; omitted in requests Closing time in 24-hour HH:MM format.
title string Optional; omitted in requests A short human-readable heading naming the exception (for example, 'Thanksgiving'). Presentation metadata that does not affect schedule evaluation.
valid_from string Required; omitted in requests The first local civil date to which this exception applies, interpreted in the containing Location's timezone.
valid_through string Required; omitted in requests The last local civil date to which this exception applies, interpreted in the containing Location's timezone.

Geo

Name Type Requirement Description
latitude number Required WGS 84 latitude in decimal degrees.
longitude number Required WGS 84 longitude in decimal degrees.

Info Code

Info code identifying the type of informational message. Standard codes are defined in capability specifications (see examples) and have standardized semantics; freeform codes are permitted.


Instrument Group

Name Type Requirement Description
types Array[string] Required Instrument types accepted by this group (OR logic). Any listed type qualifies.
min integer Optional Minimum number of instruments required from this group. Defaults to 0 (optional).
max integer Optional Maximum number of instruments allowed from this group. Defaults to 1. MUST be greater than or equal to min.

Name Type Requirement Description
type string Required Type of link. Well-known values: privacy_policy, terms_of_service, refund_policy, shipping_policy, faq. Consumers SHOULD handle unknown values gracefully by displaying them using the title field or omitting the link.
url string Required The actual URL pointing to the content to be displayed.
title string Optional Optional display text for the link. When provided, use this instead of generating from type.

Locality

Name Type Requirement Description
address_country string Optional The country, as a 2-letter ISO 3166-1 alpha-2 code (e.g. "US"). A 3-letter alpha-3 code or full country name MAY also be used.
address_region string Optional The first-level administrative region within the country (e.g. a state or province such as California).
postal_code string Optional The postal code (e.g. "94043").

Location

Name Type Requirement Description
id string Required Stable, opaque, Business-scoped Location identifier.
name string Required; omitted in requests Buyer-facing, Business-owned display name.
address Postal Address Optional; omitted in requests Physical address of the location.
geo Geo Optional; omitted in requests Geographic coordinates for the location.
amenities object Optional; omitted in requests Static features, services, or capabilities of the Location, keyed by reverse-domain amenity identifier. Each value provides a buyer-facing description; the key alone defines amenity identity and filter matching.
hours Array[Daily Hour] Optional; omitted in requests Regular weekly operating hours whose day and time values use this Location's canonical local civil-time frame. Multiple entries for the same day support split shifts. An omitted day has no regular interval beginning that day; an interval beginning on the preceding day can carry into it. Omission of the entire hours property means the regular schedule is unknown.
exception_hours Array[Exception Hour] Optional; omitted in requests Date-specific operating-hour exceptions, including full closures, whose date and time values use this Location's canonical local civil-time frame.
timezone string Optional; omitted in requests The Business-owned IANA Time Zone Database identifier (e.g., 'America/New_York') defining this Location's canonical local civil-time frame for all returned schedule day, time, and date fields. The Business does not vary this canonical framing by the requesting Platform's or Buyer's timezone. Required when hours or exception_hours is present.

Location Distance

Name Type Requirement Description
center Geo Required Explicit center of the radius. The Platform MUST supply it; the Business MUST NOT derive it from context, signals, an IP address, or serves.
max number Required Inclusive maximum distance in RFC 7035 distance unit (meters). A Business unable to honor the supplied value MUST reject the request rather than clamp it or substitute another radius.

Location Filter

Name Type Requirement Description
hours object Optional Filter by operating hours, evaluated at the one supplied instant.
amenities Array[Amenity Type] Optional Filter by amenity identifier. A Location matches only when its amenities map contains every supplied identifier as an exact key; descriptions and namespace prefixes do not participate in matching.
items Array[string] Optional Current item-availability filter. A candidate Location matches only when the Business can currently provide every referenced item at that Location; all references combine with AND.

Location Serves

Name Type Requirement Description
point Geo Optional WGS 84 coordinates of the service target.
address any Optional Coarse locality of the service target.

Location Summary

Name Type Requirement Description
id string Required Stable, opaque, Business-scoped Location identifier.
name string Required; omitted in requests Buyer-facing, Business-owned display name.
address Postal Address Optional; omitted in requests Physical address of the location.

Measure

Name Type Requirement Description
unit string Required Stable machine identifier. The Business SHOULD use the exact UN/CEFACT Rec20 Common Code when one accurately identifies the unit. Otherwise, the Business MAY use a custom unit identifier and MUST use it consistently for the same unit. The Platform MUST treat an unrecognized identifier as opaque.
scale integer Optional One step equals 10^-scale of unit. When unit is C62, scale, if present, MUST be 0. The maximum of 15 is derived from the interoperable integer range: at scale 16 a single whole unit (10^16 steps) is no longer representable, so larger scales cannot denominate one unit of their own basis. Businesses needing finer granularity use a smaller unit.
display_text string Required Required printable unit label provided by the Business. The Platform MUST use it when it does not recognize unit; for a recognized UN/CEFACT Rec 20 Common Code, the Platform MAY substitute its own localized label. It does not participate in unit identity or mismatch comparison.
value integer Required Integer count of 10^-scale units of unit.

Media

Name Type Requirement Description
type string Required Media type. Well-known values: image, video, model_3d.
url string Required URL to the media resource.
alt_text string Optional Accessibility text describing the media.
width integer Optional Width in pixels (for images/video).
height integer Optional Height in pixels (for images/video).

Message

This object MUST be one of the following types: Message Error, Message Warning, Message Info.


Message Error

Name Type Requirement Description
type string Required Constant = error. Message type discriminator.
code Error Code Required Error code identifying the type of error. Standard errors are defined in capability specifications (see examples) and have standardized semantics; freeform codes are permitted.
path string Optional RFC 9535 JSONPath to the component the message refers to (e.g., $.line_items[0]).
content_type string Optional Content format, default = plain.
Enum: plain, markdown
content string Required Human-readable message.
severity string Required Reflects the resource state and recommended action. 'recoverable': platform can resolve the condition in band, for example by modifying inputs or processing a related Action, and submit a new operation when needed. 'requires_buyer_input': merchant requires information their API doesn't support collecting programmatically (checkout incomplete). 'requires_buyer_review': buyer must authorize before order placement due to policy, regulatory, or entitlement rules. 'unrecoverable': no valid resource exists to act on, retry with new resource or inputs. Errors with 'requires_' severity contribute to 'status: requires_escalation'.
Enum:* recoverable, requires_buyer_input, requires_buyer_review, unrecoverable

Message Info

Name Type Requirement Description
type string Required Constant = info. Message type discriminator.
path string Optional RFC 9535 JSONPath to the component the message refers to (e.g., $.line_items[0]).
code Info Code Optional Info code identifying the type of informational message. Standard codes are defined in capability specifications (see examples) and have standardized semantics; freeform codes are permitted.
content_type string Optional Content format, default = plain.
Enum: plain, markdown
content string Required Human-readable message.

Message Warning

Name Type Requirement Description
type string Required Constant = warning. Message type discriminator.
path string Optional RFC 9535 JSONPath to the component the message refers to (e.g., $.line_items[0]).
code Warning Code Required Warning code identifying the type of warning. Standard codes are defined in capability specifications (see examples) and have standardized semantics; freeform codes are permitted.
content string Required Human-readable warning message that MUST be displayed.
content_type string Optional Content format, default = plain.
Enum: plain, markdown
presentation string Optional Rendering contract for this warning. 'notice' (default): platform MUST display, MAY dismiss. 'disclosure': platform MUST display in proximity to the path-referenced component, MUST NOT hide or auto-dismiss. See specification for full contract.
image_url string Optional URL to a required visual element (e.g., warning symbol, energy class label).
url string Optional Reference URL for more information (e.g., regulatory site, registry entry, policy page).

Network Token Credential

Name Type Requirement Description
type string Required The credential type discriminator. Specific schemas will constrain this to a constant value.
type any Required Constant = network_token. The credential type identifier for network token credentials.
number string Required Network token or wallet-provisioned token replacing the underlying FPAN.
expiry_month integer Optional The month of the token's expiration date (1-12).
expiry_year integer Optional The year of the token's expiration date.
name string Optional Cardholder name.
cryptogram string Required Transaction cryptogram or dynamic CVC (dCVV), in the long or short form expected by the card network or processor.
eci_value string Optional Electronic Commerce Indicator / Security Level Indicator associated with the transaction.
token_requestor_id string Optional Payment network token requestor identifier, when required by the processor or network-token program.

Pagination

Cursor-based pagination for list operations.


PAN Credential

Name Type Requirement Description
type string Required The credential type discriminator. Specific schemas will constrain this to a constant value.
type any Required Constant = pan. The credential type identifier for PAN credentials.
number string Required Funding primary account number (FPAN).
expiry_month integer Optional The month of the card's expiration date (1-12).
expiry_year integer Optional The year of the card's expiration date.
name string Optional Cardholder name.
cvc string Optional Card verification code.

Payment

Name Type Requirement Description
instruments Array[Payment Instrument Selected Payment Instrument] Optional The payment instruments available for this payment. Each instrument is associated with a specific handler via the handler_id field. Handlers can extend the base payment_instrument schema to add handler-specific fields.

Payment Credential

Name Type Requirement Description
type string Required The credential type discriminator. Specific schemas will constrain this to a constant value.

Payment Identity

Name Type Requirement Description
access_token string Required Unique identifier for this participant, obtained during onboarding with the tokenizer.

Payment Instrument

Name Type Requirement Description
id string Required A unique identifier for this instrument instance. Typically assigned by the platform for instruments it collects. For a business-owned saved instrument returned on an identity-linked response, this identifier is assigned by the business; the platform MUST treat it as an opaque, business-scoped reference, and the business resolves it server-side when the buyer selects it.
handler_id string Required The unique identifier for the handler instance that produced this instrument. This corresponds to the 'id' field in the Payment Handler definition.
type string Required The broad category of the instrument (e.g., 'card', 'tokenized_card'). Specific schemas will constrain this to a constant value.
billing_address Postal Address Optional The billing address associated with this payment method.
credential Payment Credential Optional The base definition for any payment credential. Handlers define specific credential types.
display object Optional Display information for this payment instrument. Each payment instrument schema defines its specific display properties, as outlined by the payment handler.

Payment Schedule

Name Type Requirement Description
id string Required Identifier for this payment schedule, unique within its payment term. Businesses SHOULD keep it stable across responses while the schedule remains the same payment.
type string Required Timing class, drawn from an open vocabulary. immediate is the only value with defined meaning: the payment is due when the checkout is completed. Any other value means the payment is not due at completion, and description states when it is due. Whether a due payment is authorized, captured, or settled at that moment is payment-handler behavior and outside this extension. Businesses MAY use additional values (e.g. deferred, on_shipment); Platforms MUST treat unrecognized values as not due at completion.
description Description Required Complete buyer-facing statement of when and how this payment is due. Businesses MUST make this field sufficient on its own: a Platform that recognizes no type value and reads no other field MUST be able to present this schedule correctly. Platforms MAY use type and due_at for enhanced presentation, but MUST NOT present derived timing that contradicts this field.
due_at string Optional Absolute RFC 3339 date-time when this payment is due, when the Business can determine one at checkout. Supplementary to description, never a replacement for it. Omitted when the due date depends on a future event (e.g. 'due on delivery'); the timing is then stated in description alone.
amount Amount Required The amount charged when this payment is taken, inclusive of tax and every other charge, in the Checkout currency's minor units (ISO 4217). A schedule states an amount rather than a totals breakdown: the purchase is priced once at the Checkout, and a schedule moves part or all of that price. Where the selected term changes what the purchase costs, that difference appears in checkout.totals, not here.

Payment Term

Name Type Requirement Description
id string Required Unique identifier for this payment term within the checkout. Referenced by payment.selected_term_id.
title string Required Short label that distinguishes this term from its siblings (e.g. 'Pay now', 'Pay in 4', 'Deposit + balance at check-in').
description Description Optional Supplementary context for the title (e.g. 'Save 5% by paying today'). Directly renderable; MUST NOT repeat the title.
schedules Array[Payment Schedule] Required Payment schedules that settle this checkout under this term, in the order they come due.

Policy

Name Type Requirement Description
type Reverse Domain Name Required Policy type discriminator. Open reverse-DNS vocabulary. Well-known values: dev.ucp.shopping.policy.return (return terms), dev.ucp.shopping.policy.warranty (warranty terms). Businesses MAY define custom types in their own domain (e.g., com.example.policy.price_match). Platforms MUST tolerate unknown values.
description Description Required Human-readable policy summary in one or more formats (plain, markdown, html). Required on every policy so a platform can present it without understanding any type-specific fields. This is not the buyer-facing disclosure — display is compelled by a messages[] warning (see the Policies section).
applies_to Array[string] Optional RFC 9535 JSONPath expressions identifying the nodes this policy applies to, relative to the embedding response root (e.g., $.line_items[0] in cart/checkout, $.products[2] in catalog). Each target covers the node it names and everything nested under it, so a target on a product also covers its variants. A singular query (RFC 9535 Section 2.3.5.1; name and index selectors only) names a single node; filters, wildcards, and slices match a set. When omitted, the policy applies to the entire response. When policies of the same type contest a node, the narrowest target wins and overrides the rest. See the Policies section for how specificity resolves.
url string Optional Optional link to the full policy document.

Postal Address

Name Type Requirement Description
extended_address string Optional An address extension such as an apartment number, C/O or alternative name.
street_address string Optional The street address.
address_locality string Optional The locality in which the street address is, and which is in the region. For example, Mountain View.
address_region string Optional The region in which the locality is, and which is in the country. Required for applicable countries (i.e. state in US, province in CA). For example, California or another appropriate first-level Administrative division.
address_country string Optional The country. Recommended to be in 2-letter ISO 3166-1 alpha-2 format, for example "US". For backward compatibility, a 3-letter ISO 3166-1 alpha-3 country code such as "SGP" or a full country name such as "Singapore" can also be used.
postal_code string Optional The postal code. For example, 94043.
first_name string Optional Optional. First name of the contact associated with the address.
last_name string Optional Optional. Last name of the contact associated with the address.
phone_number string Optional Optional. Phone number of the contact associated with the address.

Price

Name Type Requirement Description
amount Amount Required Amount in ISO 4217 minor units. Use 0 for free items.
currency string Required ISO 4217 currency code (e.g., 'USD', 'EUR', 'GBP').

Price Filter

Name Type Requirement Description
min Amount Optional Minimum price in ISO 4217 minor units.
max Amount Optional Maximum price in ISO 4217 minor units.

Price Range

Name Type Requirement Description
min Price Required Minimum price in the range.
max Price Required Maximum price in the range.

Quantity Unit

Name Type Requirement Description
unit string Required Stable machine identifier. The Business SHOULD use the exact UN/CEFACT Rec20 Common Code when one accurately identifies the unit. Otherwise, the Business MAY use a custom unit identifier and MUST use it consistently for the same unit. The Platform MUST treat an unrecognized identifier as opaque.
scale integer Optional One step equals 10^-scale of unit. When unit is C62, scale, if present, MUST be 0. The maximum of 15 is derived from the interoperable integer range: at scale 16 a single whole unit (10^16 steps) is no longer representable, so larger scales cannot denominate one unit of their own basis. Businesses needing finer granularity use a smaller unit.
display_text string Required Required printable unit label provided by the Business. The Platform MUST use it when it does not recognize unit; for a recognized UN/CEFACT Rec 20 Common Code, the Platform MAY substitute its own localized label. It does not participate in unit identity or mismatch comparison.
increment integer Optional Ordering granularity, denominated in steps: the Business sells this item in integer multiples of increment steps. Its effective value is the provided value or 1. Advisory merchandising policy, not a representational bound: Platform-authored quantities SHOULD be integer multiples of the effective increment; the Business MAY accept, revise, or reject an off-increment request with a recoverable business outcome and MUST NOT silently reinterpret it. Business-authored quantities (checkout revisions, fulfillment events, adjustments) are bounded only by scale.

Request Constraints

Name Type Requirement Description
path string Optional A complete RFC 9535 JSONPath query evaluated against the next logical UCP request to the same resource.
required Array[string] Optional Property names required by the constrained object. Must be non-empty: an empty array applies no constraint.
properties object Optional Constraints keyed by property name. Must be non-empty: an empty object applies no constraint.
anyOf Array[Constraint Expression] Optional Alternative Object Constraints. The constrained object must satisfy at least one. A branch must be non-empty: an empty branch is satisfied by every object and neutralizes the alternation.

Reverse Domain Name

Reverse-domain identifier used for collision-safe namespacing of capabilities, services, handlers, eligibility claims, and extension-contributed keys. Must contain at least two dot-separated segments (e.g., 'dev.ucp.shopping.checkout', 'com.example.loyalty_gold'). Segments after the first are domain- or identifier-derived: they may contain interior hyphens, may start with a digit, and may contain underscores (e.g., 'com.example-shop.checkout', 'com.2example.cart', 'dev.ucp.common.identity_linking'), but must not start or end with a hyphen. The first segment (the reversed top-level domain) is letters and digits, and may contain interior hyphens to support internationalized (punycode) top-level domains such as 'xn--p1ai'.

Pattern: ^[a-z](?:[a-z0-9-]*[a-z0-9])?(?:\.[a-z0-9](?:[a-z0-9_-]*[a-z0-9_])?)+$


Signals

Name Type Requirement Description
dev.ucp.buyer_ip string Optional Client's IP address (IPv4 or IPv6).
dev.ucp.user_agent string Optional Client's HTTP User-Agent header or equivalent.

Signed Amount

Monetary amount in the currency's minor unit as defined by ISO 4217. Refer to the currency's exponent to determine minor-to-major ratio (e.g., 2 for USD, 0 for JPY, 3 for KWD). May be negative — the sign is intrinsic to the value (e.g., discounts are negative, charges are positive).


Time Interval

Name Type Requirement Description
opens string Optional; omitted in requests Opening time in 24-hour HH:MM format.
closes string Optional; omitted in requests Closing time in 24-hour HH:MM format.

Token Credential

Name Type Requirement Description
type string Required The credential type discriminator. Specific schemas will constrain this to a constant value.
type string Required The specific type of token produced by the handler (e.g., 'stripe_token').
token string Required The token value.

Total

Name Type Requirement Description
type string Required; omitted in requests Cost category. Well-known values: subtotal, items_discount, discount, fulfillment, tax, fee, total. Businesses MAY use additional values.
display_text string Optional; omitted in requests Text to display against the amount. Should reflect appropriate method (e.g., 'Shipping', 'Delivery').
amount Signed Amount Required; omitted in requests Monetary amount in the currency's minor unit as defined by ISO 4217. Refer to the currency's exponent to determine minor-to-major ratio (e.g., 2 for USD, 0 for JPY, 3 for KWD). May be negative — the sign is intrinsic to the value (e.g., discounts are negative, charges are positive).

Totals

Pricing breakdown provided by the business. MUST contain exactly one subtotal and one total entry. Detail types (tax, fee, discount, fulfillment) may appear multiple times for itemization. Platforms MUST render all entries in order using display_text and amount.


Unit

Name Type Requirement Description
unit string Required Stable machine identifier. The Business SHOULD use the exact UN/CEFACT Rec20 Common Code when one accurately identifies the unit. Otherwise, the Business MAY use a custom unit identifier and MUST use it consistently for the same unit. The Platform MUST treat an unrecognized identifier as opaque.
scale integer Optional One step equals 10^-scale of unit. When unit is C62, scale, if present, MUST be 0. The maximum of 15 is derived from the interoperable integer range: at scale 16 a single whole unit (10^16 steps) is no longer representable, so larger scales cannot denominate one unit of their own basis. Businesses needing finer granularity use a smaller unit.
display_text string Required Required printable unit label provided by the Business. The Platform MUST use it when it does not recognize unit; for a recognized UN/CEFACT Rec 20 Common Code, the Platform MAY substitute its own localized label. It does not participate in unit identity or mismatch comparison.

Warning Code

Warning code identifying the type of warning. Standard codes are defined in capability specifications (see examples) and have standardized semantics; freeform codes are permitted.


Adjustment

Name Type Requirement Description
id string Required Adjustment event identifier.
type string Required Type of adjustment (open string). Typically money-related like: refund, return, credit, price_adjustment, dispute, cancellation. Can be any value that makes sense for the merchant's business.
occurred_at string Required RFC 3339 timestamp when this adjustment occurred.
status string Required Adjustment status.
Enum: pending, completed, failed
line_items Array[object] Optional Which line items and quantities are affected (optional).
totals Array[Total] Optional Adjustment totals breakdown. Signed values - negative for money returned to buyer (refunds, credits), positive for additional charges (exchanges).
description string Optional Human-readable reason or description (e.g., 'Defective item', 'Customer requested').

Attribution

Platform-emitted referral and conversion-event context — campaign identifiers, click IDs, source/medium markers, etc. The same parameters platforms communicate via URL query parameters in browser-based flows.


Availability

Name Type Requirement Description
available boolean Optional Whether this can be obtained. See status for fulfillment details.
status string Optional Qualifies available with fulfillment state. Well-known values: in_stock, backorder, preorder, out_of_stock, discontinued.

Business Fulfillment Config

Name Type Requirement Description
multi_destination Array[object] Optional Method types that permit multiple destinations within one cart (e.g. split shipping across addresses). Listing a method permits it; an omitted method does not. Open — businesses MAY list any method type.
method_combinations Array[array] Optional Method-type combinations the business permits within one cart. Each inner array is a permitted set of method type values (e.g. shipping + pickup).

Buyer

Name Type Requirement Description
first_name string Optional First name of the buyer.
last_name string Optional Last name of the buyer.
email string Optional Email of the buyer.
phone_number string Optional E.164 standard.

Category

Name Type Requirement Description
value string Required Category value or path (e.g., 'Apparel > Shirts', '1604').
taxonomy string Optional Source taxonomy. Well-known values: google_product_category, shopify, merchant.

Detail Option Value

Name Type Requirement Description
available boolean Optional Whether a variant matching this value and the current option selections is purchasable.
exists boolean Optional Whether a variant matching this value and the current option selections exists in the catalog.

Expectation

Name Type Requirement Description
id string Required Expectation identifier.
line_items Array[object] Required Which line items and quantities are in this expectation.
method_type string Required Delivery method type. Well-known values: shipping, pickup, digital; additional values MAY be used.
destination Postal Address Required Delivery destination address.
description string Optional Human-readable delivery description (e.g., 'Arrives in 5-8 business days').
fulfillable_on string Optional When this expectation can be fulfilled: 'now' or ISO 8601 timestamp for future date (backorder, pre-order).

Fulfillment

Name Type Requirement Description
methods Array[Fulfillment Method] Optional Fulfillment methods for cart items.
available_methods Array[Fulfillment Available Method] Optional; omitted in requests Inventory availability hints.

Fulfillment Available Method

Name Type Requirement Description
type string Required; omitted in requests Fulfillment method type this availability applies to. Well-known values: shipping, pickup; businesses MAY use additional values.
line_item_ids Array[string] Required; omitted in requests Line items available for this fulfillment method.
fulfillable_on ['string', 'null'] Optional; omitted in requests 'now' for immediate availability, or ISO 8601 date for future (preorders, transfers).
description string Optional; omitted in requests Human-readable availability info (e.g., 'Available for pickup at Downtown Store today').

Fulfillment Destination

Name Type Requirement Description
type string Required; optional in requests Destination contract discriminator. Required in Business responses and optional in Platform requests. Well-known values: shipping_address, business_location. The enclosing method contract defines request defaults and which fields the Platform may write; negotiated extensions define additional values.
id string Required; optional in requests Fulfillment destination identifier.

Fulfillment Destination Filter

Name Type Requirement Description
address_country string Optional The country, as a 2-letter ISO 3166-1 alpha-2 code (e.g. "US"). A 3-letter alpha-3 code or full country name MAY also be used.
address_region string Optional The first-level administrative region within the country (e.g. a state or province such as California).
postal_code string Optional The postal code (e.g. "94043").
location string Optional A reference to the destination (e.g. store, pickup location, saved address).

Fulfillment Event

Name Type Requirement Description
id string Required Fulfillment event identifier.
occurred_at string Required RFC 3339 timestamp when this fulfillment event occurred.
type string Required Fulfillment event type. Common values include: processing (preparing to ship), shipped (handed to carrier), in_transit (in delivery network), delivered (received by buyer), failed_attempt (delivery attempt failed), canceled (fulfillment canceled), undeliverable (cannot be delivered), returned_to_sender (returned to merchant).
line_items Array[object] Required Which line items and quantities are fulfilled in this event.
tracking_number string Optional Carrier tracking number (required if type != processing).
tracking_url string Optional URL to track this shipment (required if type != processing).
carrier string Optional Carrier name (e.g., 'FedEx', 'USPS').
description string Optional Human-readable description of the shipment status or delivery information (e.g., 'Delivered to front door', 'Out for delivery').

Fulfillment Group

Name Type Requirement Description
id string Required; omitted on create Group identifier for referencing merchant-generated groups in updates.
line_item_ids Array[string] Required; omitted in requests Line item IDs included in this group/package.
options Array[Fulfillment Option] Optional; omitted in requests Available fulfillment options for this group.
selected_option_id ['string', 'null'] Optional ID of the selected fulfillment option for this group.

Fulfillment Method

Name Type Requirement Description
id string Required; omitted on create, optional on update Unique fulfillment method identifier.
type string Required; optional on update Fulfillment method type. Well-known values: shipping, pickup. Businesses MAY use additional values.
line_item_ids Array[string] Required; omitted on create Line item IDs fulfilled via this method.
destinations Array[Fulfillment Destination] Optional; omitted in requests Available destinations for this method. In Business responses, each destination carries a type and id.
selected_destination_id ['string', 'null'] Optional ID of the selected destination. Accepts any stable, Business-scoped ID the Business recognizes for this method, including Location IDs not yet enumerated in destinations.
groups Array[Fulfillment Group] Optional Fulfillment groups for selecting options. Agent sets selected_option_id on groups to choose shipping method.

Fulfillment Option

Name Type Requirement Description
id string Required; omitted in requests Unique identifier for this fulfillment option.
title string Required; omitted in requests Short label that distinguishes this option from its siblings (e.g. 'Standard', 'Express Shipping', 'Curbside Pickup').
description Description Optional; omitted in requests Supplementary context for the title (e.g. 'Arrives in 4 business days', 'Arrives Dec 12-15 via FedEx'). Directly renderable; MUST NOT repeat the title.
carrier string Optional; omitted in requests Carrier name (for shipping).
earliest_fulfillment_time string Optional; omitted in requests Earliest fulfillment date.
latest_fulfillment_time string Optional; omitted in requests Latest fulfillment date.
totals Array[Total] Required; omitted in requests Fulfillment option totals breakdown.

Fulfillment Option Base

Name Type Requirement Description
id string Required; omitted in requests Unique identifier for this fulfillment option.
title string Required; omitted in requests Short label that distinguishes this option from its siblings (e.g. 'Standard', 'Express Shipping', 'Curbside Pickup').
description Description Optional; omitted in requests Supplementary context for the title (e.g. 'Arrives in 4 business days', 'Arrives Dec 12-15 via FedEx'). Directly renderable; MUST NOT repeat the title.

Input Correlation

Name Type Requirement Description
id string Required The identifier from the lookup request that resolved to this variant.
match string Optional How the request identifier resolved to this variant. Well-known values: exact (input directly identifies this variant, e.g., variant ID, SKU), featured (server selected this variant as representative, e.g., product ID resolved to best match). Businesses MAY implement and provide additional resolution strategies.

Item

Name Type Requirement Description
id string Required The product identifier, often the SKU, required to resolve the product details associated with this line item. Should be recognized by both the Platform, and the Business.
title string Required; omitted in requests Product title.
price Amount Required; omitted in requests Unit price in ISO 4217 minor units. Price is the amount per one whole quantity_unit.unit (for example, per lb or per hour); when quantity_unit is absent, it is per each.
quantity_unit Quantity Unit Optional Sale basis this item's quantity is denominated in. On an authoritative Business response, absence encodes the default each machine identity (C62, 0); the Business MUST include this descriptor for every non-each response. On Platform requests, omission makes no assertion: the Business interprets quantity using the item's authoritative sale basis. If the Platform includes this descriptor, it asserts the unit-descriptor machine identity. The Business MUST compare that machine identity (unit, effective scale), ignore display_text and increment, and resolve a mismatch by conversion surfaced as a visible line revision with a warning, or by rejection with a recoverable business outcome; silent reinterpretation is forbidden. An explicit C62 descriptor at effective scale 0 matches an authoritative basis represented by an absent descriptor.
unit_price Unit Price Optional; omitted in requests Pricing basis for this item. On an authoritative Business response, the Business MUST include unit_price on every line whose pricing basis differs from its sale basis (for example, priced per pound but sold per each); presence on a line marks the rate as transactional rather than display-only. When the pricing basis is the sale basis, item.price fully denominates the charge and this field MAY be omitted.
image_url string Optional; omitted in requests Product image URI.

Line Item

Name Type Requirement Description
id string Required; omitted on create, optional on update
item Item Required
quantity integer Required Always an integer step count. On Platform requests, steps use the item's Business-authoritative sale basis; omitting item.quantity_unit makes no assertion and does not imply each. On Business responses, item.quantity_unit describes the basis; if absent, it encodes the each machine identity (C62, 0) and quantity counts whole items.
totals Array[Total] Required; omitted in requests Line item totals breakdown.
parent_id string Optional; omitted on create Parent line item identifier for any nested structures.

Business Location Destination

Name Type Requirement Description
id string Required Stable, opaque, Business-scoped Location identifier.
name string Required; omitted in requests Buyer-facing, Business-owned display name.
address Postal Address Optional; omitted in requests Physical address of the location.
type string Required; omitted in requests Constant = business_location. Destination type discriminator. Response-only.

Option Value

Name Type Requirement Description
id string Optional Optional server-assigned identifier for this option value. When present in a selected_option, the server SHOULD use it for matching instead of label.
label string Required Display text for this option value (e.g., 'Small', 'Blue').

Order Confirmation

Name Type Requirement Description
id string Required Unique order identifier.
label string Optional Human-readable label for identifying the order. MUST only be provided by the business.
permalink_url string Required Permalink to access the order on merchant site.

Order Line Item

Name Type Requirement Description
id string Required Line item identifier.
item Item Required Purchased item data, including identity, price, and sale basis.
quantity object Required Tracks the line item's original, current active, and fulfilled quantities. All three values use the same inherited item.quantity_unit. When item.quantity_unit is absent on an authoritative order response, each step is one whole item (each) under the shared default.
totals Array[Total] Required Line item totals breakdown.
status string Required Derived status: removed if quantity.total == 0, fulfilled if quantity.total > 0 and quantity.fulfilled == quantity.total, partial if quantity.total > 0 and quantity.fulfilled > 0, otherwise processing.
Enum: processing, partial, fulfilled, removed
parent_id string Optional Parent line item identifier for any nested structures.

Platform Fulfillment Config

Name Type Requirement Description
supports_multi_group boolean Optional Enables multiple groups per method.

Product

Name Type Requirement Description
id string Required Global ID (GID) uniquely identifying this product.
handle string Optional URL-safe slug for SEO-friendly URLs (e.g., 'blue-runner-pro'). Use id for stable API references.
title string Required Product title.
description Description Required Product description in one or more formats.
url string Optional Canonical product page URL.
categories Array[Category] Optional Product categories with optional taxonomy identifiers.
price_range Price Range Required Price range across all variants.
list_price_range Price Range Optional List price range before discounts (for strikethrough display).
media Array[Media] Optional Product media (images, videos, 3D models). First item is the featured media for listings.
options Array[Product Option] Optional Product options (Size, Color, etc.).
variants Array[Variant] Required Purchasable variants of this product. First item is the featured variant for listings.
rating Rating Optional Aggregate product rating.
tags Array[string] Optional Product tags for categorization and search.
metadata object Optional Business-defined custom data extending the standard product model.

Product Option

Name Type Requirement Description
name string Required Option name (e.g., 'Size', 'Color').
values Array[Option Value] Required Available values for this option.

Rating

Name Type Requirement Description
value number Required Average rating value.
scale_min number Optional Minimum value on the rating scale (e.g., 1 for 1-5 stars).
scale_max number Required Maximum value on the rating scale (e.g., 5 for 5-star).
count integer Optional Number of reviews contributing to the rating.

Search Filters

Name Type Requirement Description
categories Array[string] Optional Filter by product categories (OR logic — matches products in any listed categories). Values match against the value field in product category entries. Valid values can be discovered from the categories field in search results, merchant documentation, or standard taxonomies that businesses may align with.
price Price Filter Optional Price range filter denominated in context.currency. When context.currency matches the presentment currency, businesses apply the filter directly. When it differs, businesses SHOULD convert filter values to the presentment currency before applying; if conversion is not supported, businesses MAY ignore the filter and SHOULD indicate this via a message. When context.currency is absent, filter denomination is ambiguous and businesses MAY ignore it.

Selected Option

Name Type Requirement Description
name string Required Option name (e.g., 'Size').
id string Optional Optional option value identifier from option_value.id. When present, the server SHOULD use it for matching; name and label remain required for display.
label string Required Selected option label (e.g., 'Large').

Shipping Destination

Name Type Requirement Description
extended_address string Optional An address extension such as an apartment number, C/O or alternative name.
street_address string Optional The street address.
address_locality string Optional The locality in which the street address is, and which is in the region. For example, Mountain View.
address_region string Optional The region in which the locality is, and which is in the country. Required for applicable countries (i.e. state in US, province in CA). For example, California or another appropriate first-level Administrative division.
address_country string Optional The country. Recommended to be in 2-letter ISO 3166-1 alpha-2 format, for example "US". For backward compatibility, a 3-letter ISO 3166-1 alpha-3 country code such as "SGP" or a full country name such as "Singapore" can also be used.
postal_code string Optional The postal code. For example, 94043.
first_name string Optional Optional. First name of the contact associated with the address.
last_name string Optional Optional. Last name of the contact associated with the address.
phone_number string Optional Optional. Phone number of the contact associated with the address.
id string Required; optional in requests ID specific to this shipping destination.
type string Required; optional in requests Constant = shipping_address. Destination type discriminator.

Unit Price

Name Type Requirement Description
amount Amount Required Unit price in ISO 4217 minor units. After satisfying the same-unit invariant, the Business MUST compute the comparator as (price.amount / (measure.value × 10^-measure.scale)) × (reference.value × 10^-reference.scale) and round it once to ISO 4217 minor units according to its pricing rules. The returned unit_price.amount is authoritative; the Platform MUST NOT recompute or substitute its own result.
currency string Required ISO 4217 currency code.
measure any Required Product quantity in packaging/content (for example, a 750 mL bottle), distinct from quantity_unit, which defines the sale basis. Its integer value MUST be at least 1.
reference any Required Denominator for unit price display (for example, per 100 mL or per 1 kg). Its integer value MUST be at least 1.

Variant

Name Type Requirement Description
id string Required Global ID (GID) uniquely identifying this variant. Used as item.id in checkout.
sku string Optional Business-assigned identifier for inventory and fulfillment.
barcodes Array[object] Optional Industry-standard product identifiers for cross-reference and correlation.
handle string Optional URL-safe variant handle/slug.
title string Required Variant display title (e.g., 'Blue / Large').
description Description Required Variant description in one or more formats.
url string Optional Canonical variant page URL.
categories Array[Category] Optional Variant categories with optional taxonomy identifiers.
price Price Required Current selling price. Price is the amount per one whole quantity_unit.unit (for example, per lb or per hour); when quantity_unit is absent, it is per each. Line total is price × quantity × 10^-scale, computed and rounded once by the Business; totals remain authoritative.
quantity_unit Quantity Unit Optional Sale basis this variant's quantity is denominated in. The default sale basis is each, whose machine identity is (C62, 0); C62 is the UN/CEFACT Rec20 code for one/each. An absent catalog descriptor encodes that default. An increment advertises the ordering granularity in steps (for example, scale 2 with increment 25 sells in 0.25-unit multiples).
list_price Price Optional List price before discounts (for strikethrough display).
unit_price Unit Price Optional Price per standard unit of measurement, for shelf-style comparison display. MAY be omitted when unit pricing does not apply.
availability Availability Optional Variant availability for purchase.
options Array[Selected Option] Optional Option values that define this variant (e.g., Color: Blue, Size: Large).
media Array[Media] Optional Variant media (images, videos, 3D models). First item is the featured media for listings.
rating Rating Optional Variant rating.
tags Array[string] Optional Variant tags for categorization and search.
metadata object Optional Business-defined custom data extending the standard variant model.
seller object Optional Optional seller context for this variant.

Selected Payment Instrument

A payment instrument with selection state.

Name Type Requirement Description
id string Required A unique identifier for this instrument instance. Typically assigned by the platform for instruments it collects. For a business-owned saved instrument returned on an identity-linked response, this identifier is assigned by the business; the platform MUST treat it as an opaque, business-scoped reference, and the business resolves it server-side when the buyer selects it.
handler_id string Required The unique identifier for the handler instance that produced this instrument. This corresponds to the 'id' field in the Payment Handler definition.
type string Required The broad category of the instrument (e.g., 'card', 'tokenized_card'). Specific schemas will constrain this to a constant value.
billing_address object Optional The billing address associated with this payment method.
credential object Optional The base definition for any payment credential. Handlers define specific credential types.
display object Optional Display information for this payment instrument. Each payment instrument schema defines its specific display properties, as outlined by the payment handler.
selected boolean Optional Whether this instrument is selected by the user.

Pagination Request

Pagination parameters for requests.

Name Type Requirement Description
cursor string Optional Opaque cursor from previous response.
limit integer Optional Requested page size, not a guaranteed result count. When omitted, the Business MUST apply a default page size. A default of 10 is RECOMMENDED, but the Business MAY choose another value. The Business MAY return fewer results than the requested or default page size, including when enforcing its maximum page size. A Platform MUST NOT assume that the response count equals either value.

Pagination Response

Pagination information in responses.

Name Type Requirement Description
cursor string Optional Cursor to fetch the next page of results. MUST be present when has_next_page is true.
has_next_page boolean Required Whether more results are available.
total_count integer Optional Total number of matching items, if available.

Error Code

Error code identifying the type of error. Standard errors are defined in capability specifications (see examples) and have standardized semantics; freeform codes are permitted.

Warning Code

Warning code identifying the type of warning. Standard codes are defined in capability specifications (see examples) and have standardized semantics; freeform codes are permitted.

Info Code

Info code identifying the type of informational message. Standard codes are defined in capability specifications (see examples) and have standardized semantics; freeform codes are permitted.

Extension Schemas

Loyalty Extension

Reward Amount

Non-negative integer amount denominated in the minor unit of the associated reward currency. The associated reward currency's decimal_places defines the minor-to-major ratio and defaults to 0 when omitted.

Earning Breakdown

Breakdown rule of the reward earnings

Name Type Requirement Description
id string Required Unique rewards breakdown rule identifier.
amount integer Required Rewards earned from this rule.
description string Required A display-ready, human-readable rationale for the specific rewards (e.g. 2x on footwear).
benefit_id string Optional Optional id of the membership_tier_benefit that produced this rewards rule. Resolves against membership_tier_benefit.id within the same parent loyalty membership.

Earning Forecast

Preview of rewards to be earned from the current transaction.

Name Type Requirement Description
amount integer Required Total rewards to be earned if the transaction completes.
breakdown Array[object] Optional List of breakdown of earning contributing to the total.

Reward Currency

The currency of the loyalty reward.

Name Type Requirement Description
name string Required Human-readable name of the currency (e.g. 'LoyaltyStars').
code string Required Business-specific representation of the currency (e.g. 'LST').
decimal_places integer Optional The position of a digit to the right of a decimal point. Applies to all amount related fields for rewards.

Membership Reward

Quantifiable reward type and optional earning forecast for the current transaction.

Name Type Requirement Description
currency object Required A unit of value that customers can accumulate through various commercial activities.
earning_forecast object Optional Preview of rewards to be earned from the current transaction.

Membership Tier Benefit

Benefits associated with a membership tier.

Name Type Requirement Description
id string Required Unique identifier for the tier benefit.
description string Required A display-ready, human-readable explanation of this benefit (e.g. 'Early access to sales').

Membership Tier

Specific achievement rank or status milestone that unlocks escalating value as a member progresses through activity or spend.

Name Type Requirement Description
id string Required Unique identifier for the membership tier.
name string Required The human-readable name of the tier (e.g., 'Platinum').
benefits Array[object] Optional List of benefits associated with this tier.

Loyalty Membership

Loyalty membership the business has accepted for the eligibility claim represented by the parent map key. Programs that can be joined independently MUST be modeled as separate sibling entries under the loyalty map, distinguished by reverse-domain naming (e.g., 'com.example.rewards' and 'com.example.rewards.card').

Name Type Requirement Description
id string Required Unique loyalty membership identifier.
name string Required Business specific name of the loyalty membership/program.
display_id string Optional A masked or partial version of the membership id for user recognition (e.g., '****5678'). MUST NOT be set if the membership has not been verified.
tiers Array[object] Optional Active or display-safe tier context for this membership. Most programs are single-status (one entry); programs with parallel status dimensions (e.g., current and lifetime) populate one entry per active tier. Omitted when no tier context has been resolved.
rewards Array[object] Optional Reward types and earning forecasts associated with this membership. Each object encapsulates one type of reward.
provisional boolean Required True if this membership requires additional verification.

Loyalty

Key-value map whose keys represent buyer/platform asserted eligibility claims and whose values represent associated membership information. All loyalty keys MUST use reverse-domain naming to ensure provenance and prevent collisions when multiple extensions contribute to the shared namespace.

Catalog Search with Loyalty

Catalog Search response extended with Loyalty capability.

Name Type Requirement Description
ucp any Required UCP metadata for catalog responses.
products Array[object] Required Products matching the search criteria.
pagination object Optional Pagination information in responses.
actions object Optional Outstanding extension-defined Actions for this catalog search response.
messages Array[object] Optional Errors, warnings, or informational messages about the search results.
policies Array[object] Optional Policies (e.g., return/refund terms) that apply to the products in these search results. applies_to targets are relative to the response root; when absent or empty, refer to the URLs in links[].
loyalty object Optional Key-value map whose keys represent buyer/platform asserted eligibility claims and whose values represent associated membership information. All loyalty keys MUST use reverse-domain naming to ensure provenance and prevent collisions when multiple extensions contribute to the shared namespace.

Catalog Lookup with Loyalty

Catalog Lookup response extended with Loyalty capability.

Name Type Requirement Description

Cart with Loyalty

Cart extended with Loyalty capability.

Name Type Requirement Description
ucp any Required UCP metadata for cart responses. No payment handlers needed pre-checkout.
id string Required Unique cart identifier.
line_items Array[object] Required Cart line items. Same structure as checkout. Full replacement on update.
context object Optional Buyer signals for localization (country, region, postal_code). Merchant uses for pricing, availability, currency. Falls back to geo-IP if omitted.
signals object Optional Environment data provided by the platform to support authorization and abuse prevention. Values MUST NOT be buyer-asserted claims — platforms provide signals based on direct observation or independently verifiable third-party attestations. All signal keys MUST use reverse-domain naming to ensure provenance and prevent collisions when multiple extensions contribute to the shared namespace.
attribution object Optional Platform-emitted referral and conversion-event context — campaign identifiers, click IDs, source/medium markers, etc. The same parameters platforms communicate via URL query parameters in browser-based flows.
buyer object Optional Optional buyer information for personalized estimates.
currency string Required ISO 4217 currency code. Determined by merchant based on context or geo-IP.
totals Array[Total] Required Estimated cost breakdown. May be partial if shipping/tax not yet calculable.
actions object Optional Outstanding extension-defined Actions for this cart.
messages Array[object] Optional Validation messages, warnings, or informational notices.
links Array[object] Optional Optional merchant links (policies, FAQs).
policies Array[object] Optional Policies (e.g., return/refund terms) that apply to the items in this cart. applies_to targets are relative to the response root; when absent or empty, refer to the URLs in links[].
continue_url string Optional URL for cart handoff and session recovery. Enables sharing and human-in-the-loop flows.
expires_at string Optional Cart expiry timestamp (RFC 3339). Optional.
loyalty object Optional Key-value map whose keys represent buyer/platform asserted eligibility claims and whose values represent associated membership information. All loyalty keys MUST use reverse-domain naming to ensure provenance and prevent collisions when multiple extensions contribute to the shared namespace.

Checkout with Loyalty

Checkout extended with Loyalty capability.

Name Type Requirement Description
ucp any Required UCP metadata for checkout responses.
id string Required Unique identifier of the checkout session.
line_items Array[object] Required List of line items being checked out.
buyer object Optional Representation of the buyer.
context object Optional Provisional buyer signals for relevance and localization—not authoritative data. Businesses SHOULD use these values when verified inputs (e.g., shipping address) are absent, and MAY ignore or down-rank them if inconsistent with higher-confidence signals (authenticated account, risk detection) or regulatory constraints (export controls). Eligibility and policy enforcement MUST occur at checkout time using binding transaction data. Context SHOULD be non-identifying and can be disclosed progressively—coarse signals early, finer resolution as the session progresses. Higher-resolution data (shipping address, billing address) supersedes context.
signals object Optional Environment data provided by the platform to support authorization and abuse prevention. Values MUST NOT be buyer-asserted claims — platforms provide signals based on direct observation or independently verifiable third-party attestations. All signal keys MUST use reverse-domain naming to ensure provenance and prevent collisions when multiple extensions contribute to the shared namespace.
attribution object Optional Platform-emitted referral and conversion-event context — campaign identifiers, click IDs, source/medium markers, etc. The same parameters platforms communicate via URL query parameters in browser-based flows.
status string Required Checkout state indicating the current phase and required processing. See Checkout Status lifecycle documentation for state transition details.
Enum: incomplete, requires_escalation, ready_for_complete, complete_in_progress, completed, canceled
currency string Required ISO 4217 currency code reflecting the merchant's market determination. Derived from address, context, and geo IP—buyers provide signals, merchants determine currency.
totals Array[Total] Required Different cart totals.
actions object Optional Outstanding extension-defined Actions for this checkout.
messages Array[object] Optional List of messages with error and info about the checkout session state.
links Array[object] Required Links to be displayed by the platform (Privacy Policy, TOS). Mandatory for legal compliance.
policies Array[object] Optional Policies (e.g., return/refund terms) that apply to the items in this checkout. applies_to targets are relative to the response root; when absent or empty, refer to the URLs in links[].
expires_at string Optional RFC 3339 expiry timestamp. Default TTL is 6 hours from creation if not sent.
continue_url string Optional URL for checkout handoff and session recovery. MUST be provided when status is requires_escalation. See specification for format and availability requirements.
payment object Optional Payment configuration containing handlers.
order object Optional Details about an order created for this checkout session.
loyalty object Optional Key-value map whose keys represent buyer/platform asserted eligibility claims and whose values represent associated membership information. All loyalty keys MUST use reverse-domain naming to ensure provenance and prevent collisions when multiple extensions contribute to the shared namespace.

Payment AP2 Mandate Extension

Merchant Authorization

JWS Detached Content signature (RFC 7515 Appendix F) over the checkout response body (excluding ap2 field). Format: <base64url-header>..<base64url-signature>. The header MUST contain 'alg' (ES256/ES384/ES512) and 'kid' claims. The signature covers both the header and JCS-canonicalized checkout payload.

Pattern: ^[A-Za-z0-9_-]+\.\.[A-Za-z0-9_-]+$

Checkout Mandate

SD-JWT+kb credential in ap2.checkout_mandate. Proving user authorization for the checkout. Contains the full checkout including ap2.merchant_authorization.

Pattern: ^[A-Za-z0-9_-]+\.[A-Za-z0-9_-]*\.[A-Za-z0-9_-]+(~[A-Za-z0-9_-]+)*$

Ap2 With Merchant Authorization

AP2 extension data including merchant authorization.

Name Type Requirement Description
merchant_authorization string Optional Merchant's signature proving checkout terms are authentic.

Ap2 With Checkout Mandate

AP2 extension data including checkout mandate.

Name Type Requirement Description
checkout_mandate string Optional SD-JWT+kb proving user authorized this checkout.

Checkout with AP2 Mandate

Checkout extended with AP2 mandate support.

Name Type Requirement Description
ucp any Required UCP metadata for checkout responses.
id string Required Unique identifier of the checkout session.
line_items Array[object] Required List of line items being checked out.
buyer object Optional Representation of the buyer.
context object Optional Provisional buyer signals for relevance and localization—not authoritative data. Businesses SHOULD use these values when verified inputs (e.g., shipping address) are absent, and MAY ignore or down-rank them if inconsistent with higher-confidence signals (authenticated account, risk detection) or regulatory constraints (export controls). Eligibility and policy enforcement MUST occur at checkout time using binding transaction data. Context SHOULD be non-identifying and can be disclosed progressively—coarse signals early, finer resolution as the session progresses. Higher-resolution data (shipping address, billing address) supersedes context.
signals object Optional Environment data provided by the platform to support authorization and abuse prevention. Values MUST NOT be buyer-asserted claims — platforms provide signals based on direct observation or independently verifiable third-party attestations. All signal keys MUST use reverse-domain naming to ensure provenance and prevent collisions when multiple extensions contribute to the shared namespace.
attribution object Optional Platform-emitted referral and conversion-event context — campaign identifiers, click IDs, source/medium markers, etc. The same parameters platforms communicate via URL query parameters in browser-based flows.
status string Required Checkout state indicating the current phase and required processing. See Checkout Status lifecycle documentation for state transition details.
Enum: incomplete, requires_escalation, ready_for_complete, complete_in_progress, completed, canceled
currency string Required ISO 4217 currency code reflecting the merchant's market determination. Derived from address, context, and geo IP—buyers provide signals, merchants determine currency.
totals Array[Total] Required Different cart totals.
actions object Optional Outstanding extension-defined Actions for this checkout.
messages Array[object] Optional List of messages with error and info about the checkout session state.
links Array[object] Required Links to be displayed by the platform (Privacy Policy, TOS). Mandatory for legal compliance.
policies Array[object] Optional Policies (e.g., return/refund terms) that apply to the items in this checkout. applies_to targets are relative to the response root; when absent or empty, refer to the URLs in links[].
expires_at string Optional RFC 3339 expiry timestamp. Default TTL is 6 hours from creation if not sent.
continue_url string Optional URL for checkout handoff and session recovery. MUST be provided when status is requires_escalation. See specification for format and availability requirements.
payment object Optional Payment configuration containing handlers.
order object Optional Details about an order created for this checkout session.
ap2 any Optional

AP2 Error Code

Error codes specific to AP2 mandate verification.

Enum: mandate_required, agent_missing_key, mandate_invalid_signature, mandate_expired, mandate_scope_mismatch, merchant_authorization_invalid, merchant_authorization_missing


Payment Authentication Extension

Dev.Ucp.Shopping.Checkout

Name Type Requirement Description
ucp any Required UCP metadata for checkout responses.
id string Required Unique identifier of the checkout session.
line_items Array[object] Required List of line items being checked out.
buyer object Optional Representation of the buyer.
context object Optional Provisional buyer signals for relevance and localization—not authoritative data. Businesses SHOULD use these values when verified inputs (e.g., shipping address) are absent, and MAY ignore or down-rank them if inconsistent with higher-confidence signals (authenticated account, risk detection) or regulatory constraints (export controls). Eligibility and policy enforcement MUST occur at checkout time using binding transaction data. Context SHOULD be non-identifying and can be disclosed progressively—coarse signals early, finer resolution as the session progresses. Higher-resolution data (shipping address, billing address) supersedes context.
signals object Optional Environment data provided by the platform to support authorization and abuse prevention. Values MUST NOT be buyer-asserted claims — platforms provide signals based on direct observation or independently verifiable third-party attestations. All signal keys MUST use reverse-domain naming to ensure provenance and prevent collisions when multiple extensions contribute to the shared namespace.
attribution object Optional Platform-emitted referral and conversion-event context — campaign identifiers, click IDs, source/medium markers, etc. The same parameters platforms communicate via URL query parameters in browser-based flows.
status string Required Checkout state indicating the current phase and required processing. See Checkout Status lifecycle documentation for state transition details.
Enum: incomplete, requires_escalation, ready_for_complete, complete_in_progress, completed, canceled
currency string Required ISO 4217 currency code reflecting the merchant's market determination. Derived from address, context, and geo IP—buyers provide signals, merchants determine currency.
totals Array[Total] Required Different cart totals.
actions object Optional Outstanding extension-defined Actions for this checkout.
messages Array[object] Optional List of messages with error and info about the checkout session state.
links Array[object] Required Links to be displayed by the platform (Privacy Policy, TOS). Mandatory for legal compliance.
policies Array[object] Optional Policies (e.g., return/refund terms) that apply to the items in this checkout. applies_to targets are relative to the response root; when absent or empty, refer to the URLs in links[].
expires_at string Optional RFC 3339 expiry timestamp. Default TTL is 6 hours from creation if not sent.
continue_url string Optional URL for checkout handoff and session recovery. MUST be provided when status is requires_escalation. See specification for format and availability requirements.
payment object Optional Payment configuration containing handlers.
order object Optional Details about an order created for this checkout session.
actions object Optional

Payment Split Payments Extension

Instrument Group

A constraint within an allowed combination that defines which instrument types can fill this group and how many are permitted.

Name Type Requirement Description
types Array[string] Required Instrument types accepted by this group (OR logic). Any listed type qualifies.
min integer Optional Minimum number of instruments required from this group. Defaults to 0 (optional).
max integer Optional Maximum number of instruments allowed from this group. Defaults to 1. MUST be greater than or equal to min.

Payment Instrument (Split Payments)

Payment instrument extended with an optional per-instrument amount for split payments.

Name Type Requirement Description
id string Required A unique identifier for this instrument instance. Typically assigned by the platform for instruments it collects. For a business-owned saved instrument returned on an identity-linked response, this identifier is assigned by the business; the platform MUST treat it as an opaque, business-scoped reference, and the business resolves it server-side when the buyer selects it.
handler_id string Required The unique identifier for the handler instance that produced this instrument. This corresponds to the 'id' field in the Payment Handler definition.
type string Required The broad category of the instrument (e.g., 'card', 'tokenized_card'). Specific schemas will constrain this to a constant value.
billing_address object Optional The billing address associated with this payment method.
credential object Optional The base definition for any payment credential. Handlers define specific credential types.
display object Optional Display information for this payment instrument. Each payment instrument schema defines its specific display properties, as outlined by the payment handler.
amount integer Optional Contribution amount for this instrument expressed in ISO 4217 minor units of the containing capability object's currency. On request: the platform's requested contribution (omit for open-amount). On response: the actual amount authorized or charged (omitted when not finally processed).

Checkout with Split Payments

Checkout extended with split payment instrument amounts.

Name Type Requirement Description
ucp any Required UCP metadata for checkout responses.
id string Required Unique identifier of the checkout session.
line_items Array[object] Required List of line items being checked out.
buyer object Optional Representation of the buyer.
context object Optional Provisional buyer signals for relevance and localization—not authoritative data. Businesses SHOULD use these values when verified inputs (e.g., shipping address) are absent, and MAY ignore or down-rank them if inconsistent with higher-confidence signals (authenticated account, risk detection) or regulatory constraints (export controls). Eligibility and policy enforcement MUST occur at checkout time using binding transaction data. Context SHOULD be non-identifying and can be disclosed progressively—coarse signals early, finer resolution as the session progresses. Higher-resolution data (shipping address, billing address) supersedes context.
signals object Optional Environment data provided by the platform to support authorization and abuse prevention. Values MUST NOT be buyer-asserted claims — platforms provide signals based on direct observation or independently verifiable third-party attestations. All signal keys MUST use reverse-domain naming to ensure provenance and prevent collisions when multiple extensions contribute to the shared namespace.
attribution object Optional Platform-emitted referral and conversion-event context — campaign identifiers, click IDs, source/medium markers, etc. The same parameters platforms communicate via URL query parameters in browser-based flows.
status string Required Checkout state indicating the current phase and required processing. See Checkout Status lifecycle documentation for state transition details.
Enum: incomplete, requires_escalation, ready_for_complete, complete_in_progress, completed, canceled
currency string Required ISO 4217 currency code reflecting the merchant's market determination. Derived from address, context, and geo IP—buyers provide signals, merchants determine currency.
totals Array[Total] Required Different cart totals.
actions object Optional Outstanding extension-defined Actions for this checkout.
messages Array[object] Optional List of messages with error and info about the checkout session state.
links Array[object] Required Links to be displayed by the platform (Privacy Policy, TOS). Mandatory for legal compliance.
policies Array[object] Optional Policies (e.g., return/refund terms) that apply to the items in this checkout. applies_to targets are relative to the response root; when absent or empty, refer to the URLs in links[].
expires_at string Optional RFC 3339 expiry timestamp. Default TTL is 6 hours from creation if not sent.
continue_url string Optional URL for checkout handoff and session recovery. MUST be provided when status is requires_escalation. See specification for format and availability requirements.
payment object Optional Payment configuration containing handlers.
order object Optional Details about an order created for this checkout session.
payment object Optional

Payment Terms Extension

Payment Term

A way of paying for the checkout: one or more payment schedules that together cover its total.

Name Type Requirement Description
id string Required Unique identifier for this payment term within the checkout. Referenced by payment.selected_term_id.
title string Required Short label that distinguishes this term from its siblings (e.g. 'Pay now', 'Pay in 4', 'Deposit + balance at check-in').
description object Optional Supplementary context for the title (e.g. 'Save 5% by paying today'). Directly renderable; MUST NOT repeat the title.
schedules Array[object] Required Payment schedules that settle this checkout under this term, in the order they come due.

Payment with Terms

Payment object extended with selectable payment terms.

Name Type Requirement Description
terms Array[object] Optional Payment terms the Buyer can choose from. An unselected term's amounts are indicative; the selected term's schedule amounts sum to the checkout total.
selected_term_id string Optional ID of the selected payment term. MUST match one terms[].id from the latest Checkout response. Present in a response whenever terms is, and absent when it is not: the Checkout total is the selected term's total, so a list of terms without a selection would show an amount that matches no stated term. Where the Buyer has made no choice, the Business selects a default. Omitted on create requests because term IDs are checkout-scoped and no terms exist yet, and on complete requests because the term is already agreed by then. Selecting a term is an Update Checkout mutation: the Business response is authoritative for all derived state.

Order Payment with Accepted Term

Order payment details carrying the term the Buyer accepted at checkout.

Name Type Requirement Description
accepted_term object Optional The payment term the Buyer accepted at checkout. Businesses MUST carry it forward so the Order states the amounts owed and when, and MUST ensure its schedule amounts sum to the Order total. The available terms are checkout state and are not projected.

Checkout with Payment Terms

Checkout extended with selectable payment terms.

Name Type Requirement Description
ucp any Required UCP metadata for checkout responses.
id string Required Unique identifier of the checkout session.
line_items Array[object] Required List of line items being checked out.
buyer object Optional Representation of the buyer.
context object Optional Provisional buyer signals for relevance and localization—not authoritative data. Businesses SHOULD use these values when verified inputs (e.g., shipping address) are absent, and MAY ignore or down-rank them if inconsistent with higher-confidence signals (authenticated account, risk detection) or regulatory constraints (export controls). Eligibility and policy enforcement MUST occur at checkout time using binding transaction data. Context SHOULD be non-identifying and can be disclosed progressively—coarse signals early, finer resolution as the session progresses. Higher-resolution data (shipping address, billing address) supersedes context.
signals object Optional Environment data provided by the platform to support authorization and abuse prevention. Values MUST NOT be buyer-asserted claims — platforms provide signals based on direct observation or independently verifiable third-party attestations. All signal keys MUST use reverse-domain naming to ensure provenance and prevent collisions when multiple extensions contribute to the shared namespace.
attribution object Optional Platform-emitted referral and conversion-event context — campaign identifiers, click IDs, source/medium markers, etc. The same parameters platforms communicate via URL query parameters in browser-based flows.
status string Required Checkout state indicating the current phase and required processing. See Checkout Status lifecycle documentation for state transition details.
Enum: incomplete, requires_escalation, ready_for_complete, complete_in_progress, completed, canceled
currency string Required ISO 4217 currency code reflecting the merchant's market determination. Derived from address, context, and geo IP—buyers provide signals, merchants determine currency.
totals Array[Total] Required Different cart totals.
actions object Optional Outstanding extension-defined Actions for this checkout.
messages Array[object] Optional List of messages with error and info about the checkout session state.
links Array[object] Required Links to be displayed by the platform (Privacy Policy, TOS). Mandatory for legal compliance.
policies Array[object] Optional Policies (e.g., return/refund terms) that apply to the items in this checkout. applies_to targets are relative to the response root; when absent or empty, refer to the URLs in links[].
expires_at string Optional RFC 3339 expiry timestamp. Default TTL is 6 hours from creation if not sent.
continue_url string Optional URL for checkout handoff and session recovery. MUST be provided when status is requires_escalation. See specification for format and availability requirements.
payment object Optional Payment configuration containing handlers.
order object Optional Details about an order created for this checkout session.
payment object Optional Payment details with available and selected payment terms.

Order with Accepted Payment Term

Order extended with the payment term accepted at checkout.

Name Type Requirement Description
ucp any Required UCP metadata for order responses. No payment handlers needed post-purchase.
id string Required Unique order identifier.
label string Optional Human-readable label for identifying the order. MUST only be provided by the business.
checkout_id string Required Associated checkout ID for reconciliation.
permalink_url string Required Permalink to access the order on merchant site.
line_items Array[object] Required Line items representing what was purchased — can change post-order via edits or exchanges.
fulfillment object Required Fulfillment data: buyer expectations and what actually happened.
adjustments Array[object] Optional Post-order events (refunds, returns, credits, disputes, cancellations, etc.) that exist independently of fulfillment.
currency string Required ISO 4217 currency code. MUST match the currency from the originating checkout session.
totals Array[Total] Required Different totals for the order.
policies Array[object] Optional Snapshot of the policies that applied to the items at checkout, captured on the order as a durable record. applies_to targets are relative to the response root.
messages Array[object] Optional Business outcome messages (errors, warnings, informational). Present when the business needs to communicate status or issues to the platform.
attribution object Optional Snapshot of the attribution associated with the originating checkout. Read-only on the order.
payment object Optional Payment details for the Order, including the accepted payment term.

A buyer's consent decision for a purpose (e.g., marketing, analytics). Carries the current binary state, its source (business default or platform-captured buyer decision), human-readable context, and optional refinements scoping the decision to specific channels, vendors, or programs.

Name Type Requirement Description
granted boolean Required Whether consent has been granted for this purpose. The source field identifies who asserted this state (business default or platform-captured buyer preference).
source string Required Identifies the party that asserted the current granted value. business means the value reflects the business's default policy; platform means the value reflects an explicit buyer decision captured by the platform.
Enum: business, platform
description string Required Human-readable description of what the buyer is consenting to (e.g., 'Promotional communications across all channels').
links Array[object] Optional Optional links providing context (e.g., privacy policy, terms).
segments object Optional Optional refinements scoping this purpose to specific channels, vendors, or programs. Keys are reverse-DNS identifiers. UCP currently defines two well-known segment identifiers under dev.ucp.consent.marketing: dev.ucp.consent.marketing.email, dev.ucp.consent.marketing.sms. Other segments follow vendor or merchant reverse-DNS conventions.

A buyer's consent decision for a specific refinement of a parent purpose (e.g., email marketing under the marketing purpose). Overrides the parent's granted value for this scope. Segments do not nest further.

Name Type Requirement Description
granted boolean Required Whether consent has been granted for this segment. Overrides the parent purpose's granted value for this specific scope.
source string Required Identifies the party that asserted the current granted value for this segment. business means the value reflects the business's default policy; platform means the value reflects an explicit buyer decision captured by the platform.
Enum: business, platform
description string Required Human-readable description of what the buyer is consenting to within this segment (e.g., 'Promotional emails and exclusive offers').
links Array[object] Optional Optional segment-specific links (e.g., channel terms or privacy disclosures).

Per-purpose consent. Keys are reverse-DNS purpose identifiers. UCP defines four well-known purposes: dev.ucp.consent.marketing, dev.ucp.consent.analytics, dev.ucp.consent.preferences, dev.ucp.consent.sale_or_sharing. Vendors and merchants may define additional purposes under their own reverse-DNS namespace.

Buyer object extended with per-purpose consent.

Name Type Requirement Description
first_name string Optional First name of the buyer.
last_name string Optional Last name of the buyer.
email string Optional Email of the buyer.
phone_number string Optional E.164 standard.
consent object Optional Per-purpose consent decisions and business-advertised consent options.

Cart extended with buyer consent.

Name Type Requirement Description
ucp any Required UCP metadata for cart responses. No payment handlers needed pre-checkout.
id string Required Unique cart identifier.
line_items Array[object] Required Cart line items. Same structure as checkout. Full replacement on update.
context object Optional Buyer signals for localization (country, region, postal_code). Merchant uses for pricing, availability, currency. Falls back to geo-IP if omitted.
signals object Optional Environment data provided by the platform to support authorization and abuse prevention. Values MUST NOT be buyer-asserted claims — platforms provide signals based on direct observation or independently verifiable third-party attestations. All signal keys MUST use reverse-domain naming to ensure provenance and prevent collisions when multiple extensions contribute to the shared namespace.
attribution object Optional Platform-emitted referral and conversion-event context — campaign identifiers, click IDs, source/medium markers, etc. The same parameters platforms communicate via URL query parameters in browser-based flows.
buyer object Optional Optional buyer information for personalized estimates.
currency string Required ISO 4217 currency code. Determined by merchant based on context or geo-IP.
totals Array[Total] Required Estimated cost breakdown. May be partial if shipping/tax not yet calculable.
actions object Optional Outstanding extension-defined Actions for this cart.
messages Array[object] Optional Validation messages, warnings, or informational notices.
links Array[object] Optional Optional merchant links (policies, FAQs).
policies Array[object] Optional Policies (e.g., return/refund terms) that apply to the items in this cart. applies_to targets are relative to the response root; when absent or empty, refer to the URLs in links[].
continue_url string Optional URL for cart handoff and session recovery. Enables sharing and human-in-the-loop flows.
expires_at string Optional Cart expiry timestamp (RFC 3339). Optional.
buyer any Optional Buyer with consent tracking.

Checkout extended with buyer consent.

Name Type Requirement Description
ucp any Required UCP metadata for checkout responses.
id string Required Unique identifier of the checkout session.
line_items Array[object] Required List of line items being checked out.
buyer object Optional Representation of the buyer.
context object Optional Provisional buyer signals for relevance and localization—not authoritative data. Businesses SHOULD use these values when verified inputs (e.g., shipping address) are absent, and MAY ignore or down-rank them if inconsistent with higher-confidence signals (authenticated account, risk detection) or regulatory constraints (export controls). Eligibility and policy enforcement MUST occur at checkout time using binding transaction data. Context SHOULD be non-identifying and can be disclosed progressively—coarse signals early, finer resolution as the session progresses. Higher-resolution data (shipping address, billing address) supersedes context.
signals object Optional Environment data provided by the platform to support authorization and abuse prevention. Values MUST NOT be buyer-asserted claims — platforms provide signals based on direct observation or independently verifiable third-party attestations. All signal keys MUST use reverse-domain naming to ensure provenance and prevent collisions when multiple extensions contribute to the shared namespace.
attribution object Optional Platform-emitted referral and conversion-event context — campaign identifiers, click IDs, source/medium markers, etc. The same parameters platforms communicate via URL query parameters in browser-based flows.
status string Required Checkout state indicating the current phase and required processing. See Checkout Status lifecycle documentation for state transition details.
Enum: incomplete, requires_escalation, ready_for_complete, complete_in_progress, completed, canceled
currency string Required ISO 4217 currency code reflecting the merchant's market determination. Derived from address, context, and geo IP—buyers provide signals, merchants determine currency.
totals Array[Total] Required Different cart totals.
actions object Optional Outstanding extension-defined Actions for this checkout.
messages Array[object] Optional List of messages with error and info about the checkout session state.
links Array[object] Required Links to be displayed by the platform (Privacy Policy, TOS). Mandatory for legal compliance.
policies Array[object] Optional Policies (e.g., return/refund terms) that apply to the items in this checkout. applies_to targets are relative to the response root; when absent or empty, refer to the URLs in links[].
expires_at string Optional RFC 3339 expiry timestamp. Default TTL is 6 hours from creation if not sent.
continue_url string Optional URL for checkout handoff and session recovery. MUST be provided when status is requires_escalation. See specification for format and availability requirements.
payment object Optional Payment configuration containing handlers.
order object Optional Details about an order created for this checkout session.
buyer any Optional Buyer with consent tracking.

Discount Extension

Allocation

Breakdown of how a discount amount was allocated to a specific target.

Name Type Requirement Description
path string Required RFC 9535 JSONPath to the allocation target (e.g., '$.line_items[0]', '$.totals[?@.type == "fulfillment"]').
amount integer Required Amount allocated to this target in ISO 4217 minor units.

Applied Discount

A discount that was successfully applied.

Name Type Requirement Description
code string Optional The discount code. Omitted for automatic discounts.
title string Required Human-readable discount name (e.g., 'Summer Sale 20% Off').
amount integer Required Total discount amount in ISO 4217 minor units.
automatic boolean Optional True if applied automatically by merchant rules (no code required).
method string Optional Allocation method. 'each' = applied independently per item. 'across' = split proportionally by value.
Enum: each, across
priority integer Optional Stacking order for discount calculation. Lower numbers applied first (1 = first).
provisional boolean Optional True if this discount requires additional verification.
eligibility string Optional The eligibility claim accepted by the Business for this discount. Corresponds to a value from context.eligibility. Omitted for code-based and non-eligibility automatic discounts.
allocations Array[object] Optional Breakdown of where this discount was allocated. Sum of allocation amounts equals total amount.

Discounts Object

Discount codes input and applied discounts output.

Name Type Requirement Description
codes Array[string] Optional Discount codes to apply. Case-insensitive. Replaces previously submitted codes. Send empty array to clear.
applied Array[object] Optional Discounts successfully applied (code-based and automatic).

Cart with Discount

Cart extended with discount capability.

Name Type Requirement Description
ucp any Required UCP metadata for cart responses. No payment handlers needed pre-checkout.
id string Required Unique cart identifier.
line_items Array[object] Required Cart line items. Same structure as checkout. Full replacement on update.
context object Optional Buyer signals for localization (country, region, postal_code). Merchant uses for pricing, availability, currency. Falls back to geo-IP if omitted.
signals object Optional Environment data provided by the platform to support authorization and abuse prevention. Values MUST NOT be buyer-asserted claims — platforms provide signals based on direct observation or independently verifiable third-party attestations. All signal keys MUST use reverse-domain naming to ensure provenance and prevent collisions when multiple extensions contribute to the shared namespace.
attribution object Optional Platform-emitted referral and conversion-event context — campaign identifiers, click IDs, source/medium markers, etc. The same parameters platforms communicate via URL query parameters in browser-based flows.
buyer object Optional Optional buyer information for personalized estimates.
currency string Required ISO 4217 currency code. Determined by merchant based on context or geo-IP.
totals Array[Total] Required Estimated cost breakdown. May be partial if shipping/tax not yet calculable.
actions object Optional Outstanding extension-defined Actions for this cart.
messages Array[object] Optional Validation messages, warnings, or informational notices.
links Array[object] Optional Optional merchant links (policies, FAQs).
policies Array[object] Optional Policies (e.g., return/refund terms) that apply to the items in this cart. applies_to targets are relative to the response root; when absent or empty, refer to the URLs in links[].
continue_url string Optional URL for cart handoff and session recovery. Enables sharing and human-in-the-loop flows.
expires_at string Optional Cart expiry timestamp (RFC 3339). Optional.
discounts object Optional Discount codes input and applied discounts output.

Checkout with Discount

Checkout extended with discount capability.

Name Type Requirement Description
ucp any Required UCP metadata for checkout responses.
id string Required Unique identifier of the checkout session.
line_items Array[object] Required List of line items being checked out.
buyer object Optional Representation of the buyer.
context object Optional Provisional buyer signals for relevance and localization—not authoritative data. Businesses SHOULD use these values when verified inputs (e.g., shipping address) are absent, and MAY ignore or down-rank them if inconsistent with higher-confidence signals (authenticated account, risk detection) or regulatory constraints (export controls). Eligibility and policy enforcement MUST occur at checkout time using binding transaction data. Context SHOULD be non-identifying and can be disclosed progressively—coarse signals early, finer resolution as the session progresses. Higher-resolution data (shipping address, billing address) supersedes context.
signals object Optional Environment data provided by the platform to support authorization and abuse prevention. Values MUST NOT be buyer-asserted claims — platforms provide signals based on direct observation or independently verifiable third-party attestations. All signal keys MUST use reverse-domain naming to ensure provenance and prevent collisions when multiple extensions contribute to the shared namespace.
attribution object Optional Platform-emitted referral and conversion-event context — campaign identifiers, click IDs, source/medium markers, etc. The same parameters platforms communicate via URL query parameters in browser-based flows.
status string Required Checkout state indicating the current phase and required processing. See Checkout Status lifecycle documentation for state transition details.
Enum: incomplete, requires_escalation, ready_for_complete, complete_in_progress, completed, canceled
currency string Required ISO 4217 currency code reflecting the merchant's market determination. Derived from address, context, and geo IP—buyers provide signals, merchants determine currency.
totals Array[Total] Required Different cart totals.
actions object Optional Outstanding extension-defined Actions for this checkout.
messages Array[object] Optional List of messages with error and info about the checkout session state.
links Array[object] Required Links to be displayed by the platform (Privacy Policy, TOS). Mandatory for legal compliance.
policies Array[object] Optional Policies (e.g., return/refund terms) that apply to the items in this checkout. applies_to targets are relative to the response root; when absent or empty, refer to the URLs in links[].
expires_at string Optional RFC 3339 expiry timestamp. Default TTL is 6 hours from creation if not sent.
continue_url string Optional URL for checkout handoff and session recovery. MUST be provided when status is requires_escalation. See specification for format and availability requirements.
payment object Optional Payment configuration containing handlers.
order object Optional Details about an order created for this checkout session.
discounts object Optional Discount codes input and applied discounts output.

Fulfillment Extension

Fulfillment Option

A fulfillment option within a group (e.g., Standard Shipping $5, Express $15). Extends the fulfillment option base with cost and timing.

Name Type Requirement Description
id string Required Unique identifier for this fulfillment option.
title string Required Short label that distinguishes this option from its siblings (e.g. 'Standard', 'Express Shipping', 'Curbside Pickup').
description object Optional Supplementary context for the title (e.g. 'Arrives in 4 business days', 'Arrives Dec 12-15 via FedEx'). Directly renderable; MUST NOT repeat the title.
carrier string Optional Carrier name (for shipping).
earliest_fulfillment_time string Optional Earliest fulfillment date.
latest_fulfillment_time string Optional Latest fulfillment date.
totals Array[object] Required Fulfillment option totals breakdown.

Fulfillment Group

A merchant-generated package/group of line items with fulfillment options.

Name Type Requirement Description
id string Required Group identifier for referencing merchant-generated groups in updates.
line_item_ids Array[string] Required Line item IDs included in this group/package.
options Array[object] Optional Available fulfillment options for this group.
selected_option_id ['string', 'null'] Optional ID of the selected fulfillment option for this group.

Fulfillment Method

A fulfillment method with destinations and groups.

Name Type Requirement Description
id string Required Unique fulfillment method identifier.
type string Required Fulfillment method type. Well-known values: shipping, pickup. Businesses MAY use additional values.
line_item_ids Array[string] Required Line item IDs fulfilled via this method.
destinations Array[object] Optional Available destinations for this method. In Business responses, each destination carries a type and id.
selected_destination_id ['string', 'null'] Optional ID of the selected destination. Accepts any stable, Business-scoped ID the Business recognizes for this method, including Location IDs not yet enumerated in destinations.
groups Array[object] Optional Fulfillment groups for selecting options. Agent sets selected_option_id on groups to choose shipping method.

Fulfillment Available Method

Inventory availability hint for a fulfillment method type.

Name Type Requirement Description
type string Required Fulfillment method type this availability applies to. Well-known values: shipping, pickup; businesses MAY use additional values.
line_item_ids Array[string] Required Line items available for this fulfillment method.
fulfillable_on ['string', 'null'] Optional 'now' for immediate availability, or ISO 8601 date for future (preorders, transfers).
description string Optional Human-readable availability info (e.g., 'Available for pickup at Downtown Store today').

Fulfillment

Container for fulfillment methods and availability.

Name Type Requirement Description
methods Array[object] Optional Fulfillment methods for cart items.
available_methods Array[object] Optional Inventory availability hints.

Catalog Fulfillment Method

A fulfillment method on a catalog variant: how the variant can be fulfilled, and its availability.

Name Type Requirement Description
type string Required Fulfillment method type. Well-known values: shipping, pickup. Businesses MAY use additional values.
description object Optional Short buyer-facing summary (e.g. 'Ships in 2–4 business days').
availability object Optional Availability of this variant via this method at the specified or inferred location.
location string Optional Stable, opaque identifier for the Business Location resolved for this place-based fulfillment method. The Business recognizes the same ID when submitted as selected_destination_id for that method; recognition does not reserve inventory or guarantee eligibility, and current terms are revalidated.
options Array[object] Optional Representative fulfillment options for this method (e.g. Standard, Express). Without a destination or full cart, a Business SHOULD preview meaningful boundary options (e.g. cheapest, fastest); more specific options are negotiated in Checkout once line items and destination are known.

Catalog Fulfillment

How a catalog variant can be fulfilled. Mirrors checkout fulfillment.

Name Type Requirement Description
methods Array[object] Optional Fulfillment methods for this variant.

Fulfillment Variant

A catalog variant with fulfillment.

Name Type Requirement Description
id string Required Global ID (GID) uniquely identifying this variant. Used as item.id in checkout.
sku string Optional Business-assigned identifier for inventory and fulfillment.
barcodes Array[object] Optional Industry-standard product identifiers for cross-reference and correlation.
handle string Optional URL-safe variant handle/slug.
title string Required Variant display title (e.g., 'Blue / Large').
description object Required Variant description in one or more formats.
url string Optional Canonical variant page URL.
categories Array[object] Optional Variant categories with optional taxonomy identifiers.
price object Required Current selling price. Price is the amount per one whole quantity_unit.unit (for example, per lb or per hour); when quantity_unit is absent, it is per each. Line total is price × quantity × 10^-scale, computed and rounded once by the Business; totals remain authoritative.
quantity_unit any Optional Sale basis this variant's quantity is denominated in. The default sale basis is each, whose machine identity is (C62, 0); C62 is the UN/CEFACT Rec20 code for one/each. An absent catalog descriptor encodes that default. An increment advertises the ordering granularity in steps (for example, scale 2 with increment 25 sells in 0.25-unit multiples).
list_price object Optional List price before discounts (for strikethrough display).
unit_price object Optional Price per standard unit of measurement, for shelf-style comparison display. MAY be omitted when unit pricing does not apply.
availability object Optional Variant availability for purchase.
options Array[object] Optional Option values that define this variant (e.g., Color: Blue, Size: Large).
media Array[object] Optional Variant media (images, videos, 3D models). First item is the featured media for listings.
rating object Optional Variant rating.
tags Array[string] Optional Variant tags for categorization and search.
metadata object Optional Business-defined custom data extending the standard variant model.
seller object Optional Optional seller context for this variant.
fulfillment object Optional How a catalog variant can be fulfilled. Mirrors checkout fulfillment.

Fulfillment Product

A catalog product whose variants are fulfillment-enriched. Used by search.

Name Type Requirement Description
id string Required Global ID (GID) uniquely identifying this product.
handle string Optional URL-safe slug for SEO-friendly URLs (e.g., 'blue-runner-pro'). Use id for stable API references.
title string Required Product title.
description object Required Product description in one or more formats.
url string Optional Canonical product page URL.
categories Array[object] Optional Product categories with optional taxonomy identifiers.
price_range object Required Price range across all variants.
list_price_range object Optional List price range before discounts (for strikethrough display).
media Array[object] Optional Product media (images, videos, 3D models). First item is the featured media for listings.
options Array[object] Optional Product options (Size, Color, etc.).
variants Array[object] Required Purchasable variants of this product. First item is the featured variant for listings.
rating object Optional Aggregate product rating.
tags Array[string] Optional Product tags for categorization and search.
metadata object Optional Business-defined custom data extending the standard product model.
variants Array[Variant] Required

Fulfillment Lookup Variant

A lookup variant (carrying input correlation) enriched with fulfillment.

Name Type Requirement Description
id string Required Global ID (GID) uniquely identifying this variant. Used as item.id in checkout.
sku string Optional Business-assigned identifier for inventory and fulfillment.
barcodes Array[object] Optional Industry-standard product identifiers for cross-reference and correlation.
handle string Optional URL-safe variant handle/slug.
title string Required Variant display title (e.g., 'Blue / Large').
description object Required Variant description in one or more formats.
url string Optional Canonical variant page URL.
categories Array[object] Optional Variant categories with optional taxonomy identifiers.
price object Required Current selling price. Price is the amount per one whole quantity_unit.unit (for example, per lb or per hour); when quantity_unit is absent, it is per each. Line total is price × quantity × 10^-scale, computed and rounded once by the Business; totals remain authoritative.
quantity_unit any Optional Sale basis this variant's quantity is denominated in. The default sale basis is each, whose machine identity is (C62, 0); C62 is the UN/CEFACT Rec20 code for one/each. An absent catalog descriptor encodes that default. An increment advertises the ordering granularity in steps (for example, scale 2 with increment 25 sells in 0.25-unit multiples).
list_price object Optional List price before discounts (for strikethrough display).
unit_price object Optional Price per standard unit of measurement, for shelf-style comparison display. MAY be omitted when unit pricing does not apply.
availability object Optional Variant availability for purchase.
options Array[object] Optional Option values that define this variant (e.g., Color: Blue, Size: Large).
media Array[object] Optional Variant media (images, videos, 3D models). First item is the featured media for listings.
rating object Optional Variant rating.
tags Array[string] Optional Variant tags for categorization and search.
metadata object Optional Business-defined custom data extending the standard variant model.
seller object Optional Optional seller context for this variant.
inputs Array[object] Required Which request identifiers resolved to this variant, and how. Each entry maps a request ID to its match type.
fulfillment object Optional How a catalog variant can be fulfilled. Mirrors checkout fulfillment.

Fulfillment Lookup Product

A lookup product whose variants are fulfillment-enriched, preserving input correlation. Used by lookup.

Name Type Requirement Description
id string Required Global ID (GID) uniquely identifying this product.
handle string Optional URL-safe slug for SEO-friendly URLs (e.g., 'blue-runner-pro'). Use id for stable API references.
title string Required Product title.
description object Required Product description in one or more formats.
url string Optional Canonical product page URL.
categories Array[object] Optional Product categories with optional taxonomy identifiers.
price_range object Required Price range across all variants.
list_price_range object Optional List price range before discounts (for strikethrough display).
media Array[object] Optional Product media (images, videos, 3D models). First item is the featured media for listings.
options Array[object] Optional Product options (Size, Color, etc.).
variants Array[object] Required Purchasable variants of this product. First item is the featured variant for listings.
rating object Optional Aggregate product rating.
tags Array[string] Optional Product tags for categorization and search.
metadata object Optional Business-defined custom data extending the standard product model.
variants Array[object] Required

Fulfillment Detail Product

A get_product detail product (carrying selected/options availability signals) whose variants are fulfillment-enriched. Used by get_product.

Name Type Requirement Description
selected Array[object] Optional Effective option selections that anchor the featured variant and availability signals. Required when the product has configurable options; may be empty or omitted for products with no option axes.
options Array[object] Optional Product options with availability signals relative to the effective selections.
variants Array[Variant] Optional

Fulfillment Search Filters

Catalog filters extended with a fulfillment destination filter and a method-type filter.

Name Type Requirement Description
categories Array[string] Optional Filter by product categories (OR logic — matches products in any listed categories). Values match against the value field in product category entries. Valid values can be discovered from the categories field in search results, merchant documentation, or standard taxonomies that businesses may align with.
price object Optional Price range filter denominated in context.currency. When context.currency matches the presentment currency, businesses apply the filter directly. When it differs, businesses SHOULD convert filter values to the presentment currency before applying; if conversion is not supported, businesses MAY ignore the filter and SHOULD indicate this via a message. When context.currency is absent, filter denomination is ambiguous and businesses MAY ignore it.
fulfills_to object Optional Explicit destination where items are fulfilled. It may differ from the locality or Business Location supplied in context (e.g. a gift delivered directly to the recipient). The filter restricts results to what can be fulfilled there and seeds method availability. It supersedes context only for fulfillment destination and availability resolution.
methods Array[string] Optional Restrict results to these fulfillment method types (e.g. ["pickup"]). Well-known values: shipping, pickup.

Fulfillment Search Request

Name Type Requirement Description
query string Optional Free-text search query.
context object Optional Provisional buyer signals for relevance and localization—not authoritative data. Businesses SHOULD use these values when verified inputs (e.g., shipping address) are absent, and MAY ignore or down-rank them if inconsistent with higher-confidence signals (authenticated account, risk detection) or regulatory constraints (export controls). Eligibility and policy enforcement MUST occur at checkout time using binding transaction data. Context SHOULD be non-identifying and can be disclosed progressively—coarse signals early, finer resolution as the session progresses. Higher-resolution data (shipping address, billing address) supersedes context.
signals object Optional Environment data provided by the platform to support authorization and abuse prevention. Values MUST NOT be buyer-asserted claims — platforms provide signals based on direct observation or independently verifiable third-party attestations. All signal keys MUST use reverse-domain naming to ensure provenance and prevent collisions when multiple extensions contribute to the shared namespace.
attribution object Optional Platform-emitted referral and conversion-event context — campaign identifiers, click IDs, source/medium markers, etc. The same parameters platforms communicate via URL query parameters in browser-based flows.
filters object Optional Filter criteria to narrow search results. All specified filters combine with AND logic.
pagination object Optional Pagination parameters for requests.
filters any Optional Catalog filters extended with a fulfillment destination filter and a method-type filter.

Fulfillment Search Response

Name Type Requirement Description
ucp any Required UCP metadata for catalog responses.
products Array[object] Required Products matching the search criteria.
pagination object Optional Pagination information in responses.
actions object Optional Outstanding extension-defined Actions for this catalog search response.
messages Array[object] Optional Errors, warnings, or informational messages about the search results.
policies Array[object] Optional Policies (e.g., return/refund terms) that apply to the products in these search results. applies_to targets are relative to the response root; when absent or empty, refer to the URLs in links[].
products Array[Product] Required

Fulfillment Lookup Request

Name Type Requirement Description
ids Array[string] Required Identifiers to lookup. Implementations MUST support product ID and variant ID; MAY support secondary identifiers (SKU, handle, etc.).
filters object Optional Filter criteria to narrow returned products and variants. All specified filters combine with AND logic.
context object Optional Provisional buyer signals for relevance and localization—not authoritative data. Businesses SHOULD use these values when verified inputs (e.g., shipping address) are absent, and MAY ignore or down-rank them if inconsistent with higher-confidence signals (authenticated account, risk detection) or regulatory constraints (export controls). Eligibility and policy enforcement MUST occur at checkout time using binding transaction data. Context SHOULD be non-identifying and can be disclosed progressively—coarse signals early, finer resolution as the session progresses. Higher-resolution data (shipping address, billing address) supersedes context.
signals object Optional Environment data provided by the platform to support authorization and abuse prevention. Values MUST NOT be buyer-asserted claims — platforms provide signals based on direct observation or independently verifiable third-party attestations. All signal keys MUST use reverse-domain naming to ensure provenance and prevent collisions when multiple extensions contribute to the shared namespace.
attribution object Optional Platform-emitted referral and conversion-event context — campaign identifiers, click IDs, source/medium markers, etc. The same parameters platforms communicate via URL query parameters in browser-based flows.
filters any Optional Catalog filters extended with a fulfillment destination filter and a method-type filter.

Fulfillment Lookup Response

Name Type Requirement Description
ucp any Required UCP metadata for catalog responses.
products Array[Product] Required Products matching the requested identifiers. May contain fewer items if some identifiers not found, or more if identifiers match multiple products.
actions object Optional Outstanding extension-defined Actions for this catalog lookup response.
messages Array[object] Optional Errors, warnings, or informational messages about the requested items.
policies Array[object] Optional Policies (e.g., return/refund terms) that apply to the products in this response. applies_to targets are relative to the response root; when absent or empty, refer to the URLs in links[].
products Array[Product] Required

Fulfillment Get Product Request

Name Type Requirement Description
id string Required Product or variant identifier. Implementations MUST support product ID and variant ID.
selected Array[object] Optional Partial or full option selections for interactive variant narrowing. When provided, response option values include availability signals (available, exists) relative to these selections.
preferences Array[string] Optional Option names in relaxation priority order. When no exact variant matches all selections, the server drops options from the end of this list first. E.g., ['Color', 'Size'] keeps Color and relaxes Size.
filters object Optional Filter criteria to narrow returned variants. All specified filters combine with AND logic.
context object Optional Provisional buyer signals for relevance and localization—not authoritative data. Businesses SHOULD use these values when verified inputs (e.g., shipping address) are absent, and MAY ignore or down-rank them if inconsistent with higher-confidence signals (authenticated account, risk detection) or regulatory constraints (export controls). Eligibility and policy enforcement MUST occur at checkout time using binding transaction data. Context SHOULD be non-identifying and can be disclosed progressively—coarse signals early, finer resolution as the session progresses. Higher-resolution data (shipping address, billing address) supersedes context.
signals object Optional Environment data provided by the platform to support authorization and abuse prevention. Values MUST NOT be buyer-asserted claims — platforms provide signals based on direct observation or independently verifiable third-party attestations. All signal keys MUST use reverse-domain naming to ensure provenance and prevent collisions when multiple extensions contribute to the shared namespace.
attribution object Optional Platform-emitted referral and conversion-event context — campaign identifiers, click IDs, source/medium markers, etc. The same parameters platforms communicate via URL query parameters in browser-based flows.
filters any Optional Catalog filters extended with a fulfillment destination filter and a method-type filter.

Fulfillment Get Product Response

Name Type Requirement Description
ucp any Required UCP metadata for catalog responses.
product object Required The requested product with full detail. Singular — this is a single-resource operation.
actions object Optional Outstanding extension-defined Actions for this product response.
messages Array[object] Optional Warnings or informational messages about the product (e.g., price recently changed, limited availability).
policies Array[object] Optional Policies (e.g., return/refund terms) that apply to this product. applies_to targets are relative to the response root; when absent or empty, refer to the URLs in links[].
product any Required A get_product detail product (carrying selected/options availability signals) whose variants are fulfillment-enriched. Used by get_product.

Checkout with Fulfillment

Checkout extended with hierarchical fulfillment.

Name Type Requirement Description
ucp any Required UCP metadata for checkout responses.
id string Required Unique identifier of the checkout session.
line_items Array[object] Required List of line items being checked out.
buyer object Optional Representation of the buyer.
context object Optional Provisional buyer signals for relevance and localization—not authoritative data. Businesses SHOULD use these values when verified inputs (e.g., shipping address) are absent, and MAY ignore or down-rank them if inconsistent with higher-confidence signals (authenticated account, risk detection) or regulatory constraints (export controls). Eligibility and policy enforcement MUST occur at checkout time using binding transaction data. Context SHOULD be non-identifying and can be disclosed progressively—coarse signals early, finer resolution as the session progresses. Higher-resolution data (shipping address, billing address) supersedes context.
signals object Optional Environment data provided by the platform to support authorization and abuse prevention. Values MUST NOT be buyer-asserted claims — platforms provide signals based on direct observation or independently verifiable third-party attestations. All signal keys MUST use reverse-domain naming to ensure provenance and prevent collisions when multiple extensions contribute to the shared namespace.
attribution object Optional Platform-emitted referral and conversion-event context — campaign identifiers, click IDs, source/medium markers, etc. The same parameters platforms communicate via URL query parameters in browser-based flows.
status string Required Checkout state indicating the current phase and required processing. See Checkout Status lifecycle documentation for state transition details.
Enum: incomplete, requires_escalation, ready_for_complete, complete_in_progress, completed, canceled
currency string Required ISO 4217 currency code reflecting the merchant's market determination. Derived from address, context, and geo IP—buyers provide signals, merchants determine currency.
totals Array[Total] Required Different cart totals.
actions object Optional Outstanding extension-defined Actions for this checkout.
messages Array[object] Optional List of messages with error and info about the checkout session state.
links Array[object] Required Links to be displayed by the platform (Privacy Policy, TOS). Mandatory for legal compliance.
policies Array[object] Optional Policies (e.g., return/refund terms) that apply to the items in this checkout. applies_to targets are relative to the response root; when absent or empty, refer to the URLs in links[].
expires_at string Optional RFC 3339 expiry timestamp. Default TTL is 6 hours from creation if not sent.
continue_url string Optional URL for checkout handoff and session recovery. MUST be provided when status is requires_escalation. See specification for format and availability requirements.
payment object Optional Payment configuration containing handlers.
order object Optional Details about an order created for this checkout session.
fulfillment object Optional Fulfillment details.

UCP Metadata

The following schemas define the structure of UCP metadata used in discovery and responses.

Platform Discovery Profile

The top-level structure of a platform profile document (hosted at a URI advertised by the platform).

Full UCP metadata for platform-level configuration. Hosted at a URI advertised by the platform in request headers.

Name Type Requirement Description
version string Required Version identifier in YYYY-MM-DD format.
map_order object Optional Preferred key-traversal order for sibling registry fields inside the root ucp envelope (services, capabilities, and payment_handlers).
status string Optional Application-level status of the UCP operation.
Enum: success, error
services object Required Service registry keyed by reverse-domain name.
capabilities object Optional Capability registry keyed by reverse-domain name.
payment_handlers object Required Payment handler registry keyed by reverse-domain name.
services any Required
capabilities any Optional
payment_handlers any Required

Business Discovery Profile

The top-level structure of a business discovery document (/.well-known/ucp).

UCP metadata for business/merchant-level configuration. Subset of platform schema with business-specific settings.

Name Type Requirement Description
version string Required Version identifier in YYYY-MM-DD format.
map_order object Optional Preferred key-traversal order for sibling registry fields inside the root ucp envelope (services, capabilities, and payment_handlers).
status string Optional Application-level status of the UCP operation.
Enum: success, error
services object Required Service registry keyed by reverse-domain name.
capabilities object Optional Capability registry keyed by reverse-domain name.
payment_handlers object Required Payment handler registry keyed by reverse-domain name.
supported_versions object Optional Previous protocol versions this business supports, mapped to profile URIs. Businesses that support older protocol versions SHOULD advertise each version and link to its profile. Each URI points to a complete, self-contained profile for that version. When omitted, only version is supported.
services any Required
capabilities any Optional
payment_handlers any Required

Checkout Response Metadata

The ucp object included in checkout responses.

UCP metadata for checkout responses.

Name Type Requirement Description
version string Required Version identifier in YYYY-MM-DD format.
map_order object Optional Preferred key-traversal order for sibling registry fields inside the root ucp envelope (services, capabilities, and payment_handlers).
status string Optional Application-level status of the UCP operation.
Enum: success, error
services object Optional Service registry keyed by reverse-domain name.
capabilities object Optional Capability registry keyed by reverse-domain name.
payment_handlers object Required Payment handler registry keyed by reverse-domain name.
services any Optional
capabilities any Optional
payment_handlers any Required

Cart Response Metadata

The ucp object included in cart responses.

UCP metadata for cart responses. No payment handlers needed pre-checkout.

Name Type Requirement Description
version string Required Version identifier in YYYY-MM-DD format.
map_order object Optional Preferred key-traversal order for sibling registry fields inside the root ucp envelope (services, capabilities, and payment_handlers).
status string Optional Application-level status of the UCP operation.
Enum: success, error
services object Optional Service registry keyed by reverse-domain name.
capabilities object Optional Capability registry keyed by reverse-domain name.
payment_handlers object Optional Payment handler registry keyed by reverse-domain name.
capabilities any Optional

Catalog Response Metadata

The ucp object included in catalog responses.

UCP metadata for catalog responses.

Name Type Requirement Description
version string Required Version identifier in YYYY-MM-DD format.
map_order object Optional Preferred key-traversal order for sibling registry fields inside the root ucp envelope (services, capabilities, and payment_handlers).
status string Optional Application-level status of the UCP operation.
Enum: success, error
services object Optional Service registry keyed by reverse-domain name.
capabilities object Optional Capability registry keyed by reverse-domain name.
payment_handlers object Optional Payment handler registry keyed by reverse-domain name.
capabilities any Optional

Order Response Metadata

The ucp object included in order responses or events.

UCP metadata for order responses. No payment handlers needed post-purchase.

Name Type Requirement Description
version string Required Version identifier in YYYY-MM-DD format.
map_order object Optional Preferred key-traversal order for sibling registry fields inside the root ucp envelope (services, capabilities, and payment_handlers).
status string Optional Application-level status of the UCP operation.
Enum: success, error
services object Optional Service registry keyed by reverse-domain name.
capabilities object Optional Capability registry keyed by reverse-domain name.
payment_handlers object Optional Payment handler registry keyed by reverse-domain name.
capabilities any Optional

Location Response Metadata

The ucp object included in location responses.

UCP metadata for location responses.

Name Type Requirement Description
version string Required Version identifier in YYYY-MM-DD format.
map_order object Optional Preferred key-traversal order for sibling registry fields inside the root ucp envelope (services, capabilities, and payment_handlers).
status string Optional Application-level status of the UCP operation.
Enum: success, error
services object Optional Service registry keyed by reverse-domain name.
capabilities object Optional Capability registry keyed by reverse-domain name.
payment_handlers object Optional Payment handler registry keyed by reverse-domain name.
capabilities any Optional

Capability

This object describes a single capability or extension. It appears in the capabilities array in discovery profiles and responses, with slightly different required fields in each context.

Capability (Discovery)

As seen in discovery profiles.

Full capability declaration for platform-level discovery. Includes spec/schema URLs for agent fetching.

Name Type Requirement Description
version string Required Entity version in YYYY-MM-DD format.
spec string Required URL to human-readable specification document.
schema string Required URL to JSON Schema defining this entity's structure and payloads.
id string Optional Unique identifier for this entity instance. Used to disambiguate when multiple instances exist.
config object Optional Entity-specific configuration. Structure defined by each entity's schema.
extends OneOf[string, array] Optional Parent capability(s) this extends. Present for extensions, absent for root capabilities. Use array for multi-parent extensions.

Capability (Response)

As seen in response messages.

Capability reference in responses. Only name/version required to confirm active capabilities.

Name Type Requirement Description
version string Required Entity version in YYYY-MM-DD format.
spec string Optional URL to human-readable specification document.
schema string Optional URL to JSON Schema defining this entity's structure and payloads.
id string Optional Unique identifier for this entity instance. Used to disambiguate when multiple instances exist.
config object Optional Entity-specific configuration. Structure defined by each entity's schema.
extends OneOf[string, array] Optional Parent capability(s) this extends. Present for extensions, absent for root capabilities. Use array for multi-parent extensions.