UCP is expanding to new industries, starting with Lodging and Food Detailed specifications coming soon! # Universal Commerce Protocol The common language for platforms, agents, and businesses. UCP provides building blocks for agentic commerce across industries—from discovery to checkout and beyond—allowing the ecosystem to operate through one standard, without custom builds. ### Learn Protocol overview, core concepts, and design principles [Get Started](http://ucp.dev/latest/specification/overview/index.md) ### Implement GitHub repo, technical spec, SDKs, and reference implementations [View on GitHub](https://github.com/Universal-Commerce-Protocol/ucp) ## Co-developed by industry leaders UCP is built by the industry, to enable seamless agentic experiences. It solves fragmented user journeys that lead to frustrated users and conversion drop off. Shopping Lodging Food Google Shopify Etsy Wayfair Target Walmart Amazon Microsoft Meta Salesforce Stripe Amadeus Booking.com Expedia Group Google Hilton Marriott Trip.com DoorDash Google Square Toast Uber Eats ## Built for flexibility, security, and scale Agentic commerce requires interoperability. UCP is built on industry standards — REST and JSON-RPC transports; [Agent Payments Protocol (AP2)](https://ap2-protocol.org/), [Agent2Agent (A2A)](https://a2a-protocol.org/latest/), and [Model Context Protocol (MCP)](https://modelcontextprotocol.io/docs/getting-started/intro) support built-in — so different systems can work together without custom integration. ### Scalable and universal Surface-agnostic design that scales to support any business (from small to enterprise), in every industry, across all modalities, including chat, visual commerce, and voice. ### Businesses at the center Built to facilitate commerce, ensuring businesses retain control and remain the Merchant of Record, with full ownership of customer relationships. ### Open and extensible Open and extensible by design, enabling development of community-driven capabilities and extensions across industries. ### Secure and private Built on proven security standards for account linking (OAuth 2.0) and secure payment (AP2) via payment mandates and verifiable credentials. ### Frictionless payments Open wallet ecosystem with interoperability between providers, ensuring buyers can use their preferred payment methods. ## See it in action UCP is designed to facilitate the entire commerce lifecycle, from discovery and search to final sale and post-purchase support. The protocol supports a range of core capabilities, including: Catalog Search and Lookup, Cart Building, Identity Linking, Checkout, and Order Management. Shopping Lodging Food Checkout Identity Linking Order ### Checkout Support complex cart logic, dynamic pricing, tax calculations, and more across millions of businesses through unified checkout sessions. [Get Started](http://ucp.dev/latest/specification/shopping/checkout/index.md) ```json { "ucp": { ... }, "id": "chk_123456789", "status": "ready_for_complete", "currency": "USD", "buyer": { "email": "e.beckett@example.com", "first_name": "Elisa", "last_name": "Beckett" }, "line_items": [ { "id": "li_1", "item": { "id": "item_123", "title": "Monos Carry-On Pro suitcase", "price": 26550 }, "quantity": 1, ... } ], "totals": [ ... ], "links": [ ... ], "payment": { ... }, "fulfillment": { "methods": [ { "id": "method_1", "type": "shipping", "line_item_ids": ["li_1"], "selected_destination_id": "dest_1", "destinations": [ { "type": "shipping_address", "id": "dest_1", "first_name": "Elisa", "last_name": "Beckett", "street_address": "1600 Amphitheatre Pkwy", "address_locality": "Mountain View", "address_region": "CA", "postal_code": "94043", "address_country": "US" } ], "groups": [ { "id": "group_1", "line_item_ids": ["li_1"], "selected_option_id": "free-shipping", "options": [ { "id": "free-shipping", "title": "Free Shipping", "totals": [ {"type": "total", "amount": 0} ] } ] } ] } ] } } ``` ### Identity Linking OAuth 2.0 standard enables agents to maintain secure, authorized relationships without sharing credentials. [Get Started](http://ucp.dev/latest/specification/common/identity-linking/index.md) ```json Sample of /.well-known/oauth-authorization-server { "issuer": "https://example.com", "authorization_endpoint": "https://example.com/oauth2/authorize", "token_endpoint": "https://example.com/oauth2/token", "revocation_endpoint": "https://example.com/oauth2/revoke", "scopes_supported": [ "dev.ucp.shopping.checkout" ], "response_types_supported": [ "code" ], "grant_types_supported": [ "authorization_code", "refresh_token" ], "token_endpoint_auth_methods_supported": [ "client_secret_basic" ], "service_documentation": "https://example.com/docs/oauth2" } ``` ### Order From purchase confirmation to delivery. Real-time webhooks power status updates, shipment tracking, and return processing across every channel. [Get Started](http://ucp.dev/latest/specification/shopping/order/index.md) ```json { "ucp": { ... }, "id": "order_123456789", "checkout_id": "chk_123456789", "permalink_url": ..., "line_items": [ ... ], "fulfillment": { "expectations": [ { "id": "exp_1", "line_items": [{ "id": "li_1", "quantity": 1 }], "method_type": "shipping", "destination": { "first_name": "Elisa", "last_name": "Beckett", "street_address": "1600 Amphitheatre Pkwy", "address_locality": "Mountain View", "address_region": "CA", "postal_code": "94043", "address_country": "US" }, "description": "Arrives in 2-3 business days", "fulfillable_on": "now" } ... ], "events": [ { "id": "evt_1", "occurred_at": "2026-01-11T10:30:00Z", "type": "delivered", "line_items": [{ "id": "li_1", "quantity": 1 }], "tracking_number": "123456789", "tracking_url": "https://fedex.com/track/123456789", "description": "Delivered to front door" } ] }, "adjustments": [ { "id": "adj_1", "type": "refund", "occurred_at": "2026-01-12T14:30:00Z", "status": "completed", "line_items": [{ "id": "li_1", "quantity": -1 }], "totals": [{ "type": "total", "amount": -26550 }], "description": "Defective item" } ], "totals": [ ... ] } ``` ### Lodging Enables high-quality booking flows within AI surfaces—complete with real-time pricing and availability checks, smooth handling of complex rate plans, easy guest registration, and secure checkout. [Learn more](https://developers.google.com/hotels/ucp) Detailed specifications coming soon ### Food Powers conversational food ordering journeys that seamlessly handle nuanced meal customization, real-time availability and deals, tipping, and delivery instructions through a scalable checkout experience on AI surfaces. [Learn more](https://developers.google.com/actions-center/verticals/ordering/ucp) Detailed specifications coming soon ### Power native checkout Integrate and negotiate directly with a seller's checkout API to power native UI and workflows for your platform. [Get Started](http://ucp.dev/latest/specification/shopping/checkout/rest/index.md) ### Embed business checkout Embed and render business checkout UI to support complex checkout flows, with advanced capabilities like bidirectional communication, and payment and shipping address delegation. [See how it works](http://ucp.dev/latest/specification/shopping/checkout/embedded/index.md) ## Designed for the entire commerce ecosystem ### For Developers Build the future of commerce on an open foundation. Join our community in evolving an open-source standard designed for the next generation of digital commerce. [View the technical spec](http://ucp.dev/latest/specification/overview/index.md) ### For Businesses UCP empowers businesses to meet customers wherever they are—AI assistants, agents, embedded experiences—without rebuilding your checkout for each. You remain the Merchant of Record and your business logic stays intact. [Integrate with UCP](https://developers.google.com/merchant/ucp/) ### For AI Platforms Simplify business onboarding with standardized APIs and provide your audience with an integrated agentic commerce experience. Compatible with MCP, A2A, and existing agent frameworks. [Learn more about UCP core concepts](http://ucp.dev/documentation/core-concepts/index.md) ### For Payment Providers Universal payments that are provable—every authorization backed by cryptographic proof of user consent. Open, modular payment handler design enables open interoperability and choice of payment methods. [Learn more about UCP and AP2](http://ucp.dev/documentation/ucp-and-ap2/index.md) ## Endorsed across the ecosystem Accor Adore Beauty Adyen Affirm Amadeus Amex Ant International Best Buy Block Booking.com Bunnings Carrefour Checkout.com Chewy Choice Hotels Commerce DoorDash Expedia Group Fiserv Flipkart Gap Hilton Iconic IHG Klarna Kogan Kroger Lowe's Macy's Marriott Mastercard Paypal Petbarn Salesforce SAP Sephora Shopee Splitit Square Stripe The Home Depot Toast Trip.com Uber Eats Ulta Visa VTEX Worldpay Wyndham Zalando Accor Adore Beauty Adyen Affirm Amadeus Amex Ant International Best Buy Block Booking.com Bunnings Carrefour Checkout.com Chewy Choice Hotels Commerce DoorDash Expedia Group Fiserv Flipkart Gap Hilton Iconic IHG Klarna Kogan Kroger Lowe's Macy's Marriott Mastercard Paypal Petbarn Salesforce SAP Sephora Shopee Splitit Square Stripe The Home Depot Toast Trip.com Uber Eats Ulta Visa VTEX Worldpay Wyndham Zalando ## Get started today UCP is an open standard designed to let AI agents, apps, businesses, and payment providers interact seamlessly without needing custom, one-off integrations for every connection. We actively seek your feedback and contributions to help build the future of commerce. The complete technical specification, documentation, and reference implementations are hosted in our public GitHub repository. ### [Download](https://github.com/Universal-Commerce-Protocol/samples) Download and run our code samples ### [Experiment](http://ucp.dev/latest/specification/shopping/playground/index.md) Experiment with the protocol and its different agent roles ### [Contribute](https://github.com/Universal-Commerce-Protocol/.github/blob/main/CONTRIBUTING.md) Contribute your feedback and code to the public repository [Visit the GitHub repository](https://github.com/Universal-Commerce-Protocol/ucp)