Agent Payments Protocol (AP2) vs Universal Commerce Protocol (UCP)
The map lists them as complementary: sites and agents commonly implement both. Universal Commerce Protocol is a prerequisite of Agent Payments Protocol. Agent Payments Protocol is a prerequisite of Universal Commerce Protocol.
| Agent Payments Protocol AP2 | Universal Commerce Protocol UCP | |
|---|---|---|
| Lifecycle step | 7 Pay: Settle the bill | 7 Pay: Settle the bill |
| Answers | Did the user actually authorize what this agent is about to buy and pay for, and can the merchant prove it later? | Can an agent discover a business's commerce capabilities, build a cart, and check out interoperably across shopping, lodging, and food ordering? |
| Governed by | Google; core specification donated to the FIDO Alliance (Payments TWG and Agentic Authentication TWG), 2026-04-28; the google-agentic-commerce/AP2 repository now hosts only samples and an SDK, not the normative spec text | Domain Tech Councils (DTC) per vertical — Shopping Tech Council and Food Tech Council seated — under an overall Governing Council (GC); DTC seats held by Google, Shopify, Etsy, Meta, Amazon, Microsoft, Target, Stripe, Salesforce, Wayfair, Square, Toast, DoorDash, Uber Eats |
| Status (issuer's words) | Security/authorization protocol for agent-performed payments; core spec now stewarded by FIDO Alliance | Open standard; specification expanding beyond Shopping into Lodging and Food |
| Version | v0.2.0 (2026-04-28) | v2026-08-25 (2026-08-25) |
| Form / transport | endpoint | well-known file |
| Found at | none | /.well-known/ucp |
| Implementation | multi-implementation — Google (launch blog post, 60+ launch partners) | multi-implementation — UCP project (ucp.dev launch-partner list) |
| Evidence | 4 verified, 2 reported | 5 verified, 1 reported |
| Primary use case | Let agents buy on behalf of a person | Let agents buy on behalf of a person |
| Last verified | 2026-10-23 (current) | 2026-10-23 (current) |
| Specification | https://raw.githubusercontent.com/google-agentic-commerce/AP2/main/docs/ap2/specification.md | https://ucp.dev/documentation/core-concepts/ |
When to use which
- Choose Agent Payments Protocol when your question is “Did the user actually authorize what this agent is about to buy and pay for, and can the merchant prove it later?” and you accept its maturity: status "Security/authorization protocol for agent-performed payments; core spec now stewarded by FIDO Alliance", implementation multi-implementation (Google (launch blog post, 60+ launch partners)).
- Choose Universal Commerce Protocol when your question is “Can an agent discover a business's commerce capabilities, build a cart, and check out interoperably across shopping, lodging, and food ordering?” and you accept its maturity: status "Open standard; specification expanding beyond Shopping into Lodging and Food", implementation multi-implementation (UCP project (ucp.dev launch-partner list)).
Read the full articles
- Agent Payments Protocol: Did the user actually authorize what this agent is about to buy and pay for, and can the merchant prove it later?
- Universal Commerce Protocol: Can an agent discover a business's commerce capabilities, build a cart, and check out interoperably across shopping, lodging, and food ordering?