# Universal Commerce Protocol (UCP)

> The Universal Commerce Protocol (UCP) is a solution for enabling gen AI agents to make payments on behalf of users, safely, securely, and in a decentralized and privacy protecting manner. This protocol is a part of the broader ecosystem, which includes agentic protocols like A2A and MCP, and encompasses the global nature of payments.


## Specification

- [Overview](http://ucp.dev/2026-04-08/specification/overview/index.md)

## Message Signatures

- [Signatures](http://ucp.dev/2026-04-08/specification/signatures/index.md)

## Checkout Capability

- [Overview](http://ucp.dev/2026-04-08/specification/checkout/index.md)
- [REST](http://ucp.dev/2026-04-08/specification/checkout-rest/index.md)
- [MCP](http://ucp.dev/2026-04-08/specification/checkout-mcp/index.md)
- [A2A](http://ucp.dev/2026-04-08/specification/checkout-a2a/index.md)
- [Embedded protocol](http://ucp.dev/2026-04-08/specification/embedded-protocol/index.md)
- [Embedded](http://ucp.dev/2026-04-08/specification/embedded-checkout/index.md)
- [AP2 Mandates Extension](http://ucp.dev/2026-04-08/specification/ap2-mandates/index.md)
- [Buyer Consent Extension](http://ucp.dev/2026-04-08/specification/buyer-consent/index.md)
- [Discounts Extension](http://ucp.dev/2026-04-08/specification/discount/index.md)
- [Fulfillment Extension](http://ucp.dev/2026-04-08/specification/fulfillment/index.md)

## Cart Capability

- [Overview](http://ucp.dev/2026-04-08/specification/cart/index.md)
- [REST](http://ucp.dev/2026-04-08/specification/cart-rest/index.md)
- [MCP](http://ucp.dev/2026-04-08/specification/cart-mcp/index.md)
- [Embedded protocol](http://ucp.dev/2026-04-08/specification/embedded-protocol/index.md)
- [Embedded](http://ucp.dev/2026-04-08/specification/embedded-cart/index.md)

## Catalog Capability

- [Overview](http://ucp.dev/2026-04-08/specification/catalog/index.md)
- [Search](http://ucp.dev/2026-04-08/specification/catalog/search/index.md)
- [Lookup](http://ucp.dev/2026-04-08/specification/catalog/lookup/index.md)
- [REST](http://ucp.dev/2026-04-08/specification/catalog/rest/index.md)
- [MCP](http://ucp.dev/2026-04-08/specification/catalog/mcp/index.md)

## Other Capabilities

- [Overview](http://ucp.dev/2026-04-08/specification/order/index.md)
- [REST](http://ucp.dev/2026-04-08/specification/order-rest/index.md)
- [MCP](http://ucp.dev/2026-04-08/specification/order-mcp/index.md)
- [Identity Linking Capability](http://ucp.dev/2026-04-08/specification/identity-linking/index.md)
- [Guide](http://ucp.dev/2026-04-08/specification/payment-handler-guide/index.md)
- [Template](http://ucp.dev/2026-04-08/specification/payment-handler-template/index.md)
- [Tokenization Guide](http://ucp.dev/2026-04-08/specification/tokenization-guide/index.md)
- [Processor Tokenizer](http://ucp.dev/2026-04-08/specification/examples/processor-tokenizer-payment-handler/index.md)
- [Platform Tokenizer](http://ucp.dev/2026-04-08/specification/examples/platform-tokenizer-payment-handler/index.md)
- [Encrypted Credential](http://ucp.dev/2026-04-08/specification/examples/encrypted-credential-handler/index.md)
- [Reference](http://ucp.dev/2026-04-08/specification/reference/index.md)
- [Playground](http://ucp.dev/2026-04-08/specification/playground/index.md)