Quick Start by Role

Choose the path that matches your role in the UCP ecosystem.

Business (UCP Server Implementer)

For retailers, merchants, and commerce platforms that want to expose their store via UCP so that platforms and agents can discover and transact with them.

core-concepts.md — understand the four UCP roles, capability model, and discovery mechanism
../reference/specification-overview.md — protocol rules, namespace governance, and capability negotiation
../capabilities/catalog/overview.md — expose your product catalog to platforms and agents
../capabilities/cart/overview.md — cart lifecycle and line-item management
../capabilities/checkout/overview.md — checkout session flow and status lifecycle
../capabilities/checkout/fulfillment.md — shipping and pickup fulfillment options
../capabilities/checkout/discounts.md — discount code support as a checkout extension
../capabilities/checkout/ap2-mandates.md — cryptographic payment authorization for autonomous agents
../payment-handlers/guide.md — configure which payment methods your business accepts
../capabilities/order.md — post-purchase webhooks and order lifecycle events
../capabilities/identity-linking.md — link user accounts to your store via OAuth 2.0
../security/signatures.md — sign and verify HTTP messages to authenticate requests

Platform / Agent Developer

For AI assistants, browser extensions, and agents that drive shopping on behalf of users across one or many businesses.

core-concepts.md — understand the platform role, capability discovery, and supported transports (REST, MCP, A2A)
../capabilities/catalog/overview.md + search.md + lookup.md — discover and retrieve products from business catalogs
../capabilities/cart/overview.md — build, modify, and manage carts programmatically
../capabilities/checkout/overview.md — drive checkout sessions and interpret status transitions
../capabilities/checkout/embedded.md — surface embedded business UIs within browser contexts
../capabilities/checkout/buyer-consent.md — handle GDPR/CCPA consent prompts during checkout
../capabilities/order.md — subscribe to order lifecycle events after purchase
../capabilities/identity-linking.md — link your platform user to a business account via OAuth 2.0
../security/signatures.md — authenticate your outbound requests with HTTP message signatures
../getting-started/versioning.md — capability negotiation and protocol version compatibility with businesses

Payment / Credential Provider

For PSPs, digital wallets, and tokenization layers that want to be discoverable as payment handlers within the UCP ecosystem.

core-concepts.md — understand where credential providers and PSPs fit in the UCP protocol
../payment-handlers/guide.md — the full payment handler framework: participants, prerequisites, configuration, and execution
../payment-handlers/examples/processor-tokenizer.md — PSP-owned tokenization pattern
../payment-handlers/examples/platform-tokenizer.md — platform wallet tokenization pattern
../payment-handlers/examples/encrypted-credential.md — encrypted credential pattern
../payment-handlers/template.md — starter template for authoring your own handler specification
../payment-handlers/tokenization.md — tokenization implementation deep-dive
../capabilities/checkout/ap2-mandates.md — AP2 mandate signing requirements for autonomous payment authorization
../advanced/ucp-and-ap2.md — AP2 integration architecture and how it connects to UCP checkout
../security/signatures.md — cryptographic signing requirements for payment handler responses