UCP integration
Exchange and lifecycle
- Capability discovery and version negotiation
- Cart or checkout session contracts
- Payment-handler configuration
- Identity-linking extension
- Order lifecycle updates
Interactive field guide · reviewed 04 Sep 2026
UCP Merchant Readiness Checklist
Going live takes more than publishing a protocol profile. Check the integration path Google validates—and the merchant controls UCP does not make for you.
Protocol configured≠Governance ready≠Google approval
The score is an independent planning signal—not certification or approval.
Before you check boxes
Choose the path before judging readiness.
Google documents different validation paths for cart transfer and native checkout. Identity linking is optional and sits on the native-checkout path; guest checkout is the documented alternative.
The assessment changes its implementation items when you switch paths. Governance controls remain visible because commercial authority and evidence still matter in either flow.
Self-assessment
Build an evidence-backed readiness picture.
Mark an item only when you can point to its evidence. Your selections are held in memory for this tab and are never sent to AgentGateFee.
UCP implementation
Documented Google integration and validation path
Merchant governance
Merchant-owned controls outside protocol conformance
Protocol boundary
Passing messages is not the same as granting authority.
UCP defines interoperable commerce capabilities. The merchant remains responsible for deciding which principals to trust, what they may do, and what evidence must survive the decision.
Merchant governance
Authority and evidence
- Trusted principal and delegated authority
- Price, quantity, geography, and risk policy
- Human-review and fail-closed conditions
- Explainable decision evidence
- Cross-system state reconciliation
Primary-source ledger
What this checklist is based on
Implementation items follow Google's current merchant documentation. Governance items are explicitly presented as merchant controls—not as Google UCP requirements.
- 01Google — UCP implementation overview
Merchant Center, Google Pay, UCP profile, native checkout, identity choice, and order-status sequence.
- 02Google — Start UCP integration in Merchant Center
Capability selection, sandbox tests, profile validation, production review, and the UCP Program Addendum.
- 03Google — Prepare your UCP profile
Public discovery document for versions, capabilities, endpoints, payment handlers, and signing keys.
- 04Google — Native checkout overview
Checkout session API flow, lifecycle states, and the buyer handoff to Google UI.
- 05Google — Identity Linking with OAuth 2.0
OAuth scopes, authorization metadata, token use, and guest-checkout fallback.
- 06Google — Order lifecycle
Required post-purchase order events and Google webhook delivery.
Readiness notes
What the score does—and does not—mean
Does completing this checklist mean Google will approve the integration?
No. This is an independent readiness aid. Google validates selected capabilities and reviews the integration before it can go live on supported Google surfaces.
Is identity linking required for UCP checkout?
Not in every path. Google documents guest checkout as the default option. Account-linked checkout requires OAuth 2.0, the required scopes, capability declaration, and published authorization-server metadata.
Is a public UCP profile enough to go live?
No. The profile enables capability discovery and negotiation, but the selected APIs, sandbox tests, production validation, and applicable onboarding steps must also be completed.
Why does the checklist separate implementation from governance?
Protocol conformance explains how systems exchange commerce data. A merchant still needs its own controls for trusted principals, delegated authority, policy limits, escalation, evidence, and state reconciliation.
Next step after the checklist