UCP vs AP2
Where does commerce state end and purchase authority begin?
UCP models commerce capabilities. AP2 specifies authorization evidence inside a commerce context. AP2’s current specification explicitly describes compatibility with UCP. Map checkout and fulfillment data with the commerce implementation. Separately assign the parties that produce and verify mandates and receipts. They can complement each other.
What this establishes
A practical way to inspect evidence and make the next merchant decision.
What it cannot establish
An unresolved dependency remains. Treat affected claims as provisional. Live merchant deployment, private account eligibility, purchase completion or guaranteed AI selection.
The overlap
UCP models commerce capabilities. AP2 specifies authorization evidence inside a commerce context. AP2’s current specification explicitly describes compatibility with UCP.
The merchant decision
Map checkout and fulfillment data with the commerce implementation. Separately assign the parties that produce and verify mandates and receipts. They can complement each other.
Where they overlap.
Where they complement.
Compare roles and implementation work. A shared capability does not make two systems interchangeable.
| Decision dimension | UCP | AP2 |
|---|---|---|
| Layer | Commerce | Identity & trust |
| Role | Connects catalog, cart, checkout and related commerce capabilities across implementations. | Uses linked checkout/payment mandates and receipts to bind authorization. |
| Status | released | released |
| Version | 2026-08-25 | 0.2.0 |
| Discovery | /.well-known/ucp profile; optional catalog capability | Outside scope |
| Checkout | Commerce checkout capability | Authorizes checkout; does not define commerce API |
| Payment | Payment handlers; complements authorization protocols | Mandates and receipts; not a settlement rail |
| Authorization | Can work with AP2; capability-specific | Core role |
| Transport | REST, MCP and A2A bindings documented | Integration with commerce protocols |
| Adoption | Google and Shopify describe scoped implementations | Public specification; individual deployments Unknown |
| What it does not solve | Does not make every declared capability live on every shopping surface. | Does not define the catalog API or replace a commerce protocol. |
| Evidence | 5 source record(s) Checked 2026-09-28 live; scope-dependent | 3 source record(s) Checked 2026-09-28 public-preview; scope-dependent |
Unknown ≠ unsupported. Announcements and product documentation are not proof of your live integration.
Overlap and replacement risk
These entries occupy different layers. They can work together; replacing one with another may leave a commerce, communication or authorization gap. Keep your source of product truth, fulfillment responsibility and payment obligations explicit.
Go to the source.
Primary documentation records what is publicly stated. It does not independently prove outcomes or your account’s eligibility.
Claim scope: Discovery profile and commerce capabilities
Version-pinned profile discovery; declared capabilities do not prove successful transactions.
Claim scope: Commerce semantics and interoperability
Claim scope: UCP merchant integration hub and AI performance insights
US rollout; later markets are future plans. Scale/performance statements are Google claims.
Claim scope: Developer UCP and Catalog access
Self-serve developer access. Conversion metrics in the article are vendor claims, not our results.
Claim scope: Version metadata and documented changes only; not merchant adoption.
SHA-256 of retrieved source response: a554d5a172bb62d0d22abda152b99817fddd9735f434866d1c49863274dc049c
Claim scope: Authorization mandates and receipts
Payment authorization within a commerce protocol; catalog API details are out of scope.
Claim scope: Stewardship and integrations
Site states continued standardization within FIDO working groups.
Claim scope: Version metadata and documented changes only; not merchant adoption.
SHA-256 of retrieved source response: 43572d4defa8d53e8ab8dbfe90cc2d6734892aa93fcce009015d73cf21336ad6