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Agent Payments Protocol AP2

Pay The Agent Payments Protocol (AP2) is a security and authorization framework for agent-performed payments: it defines how a user's intent to buy something is captured as a cryptographically signed, tamper-evident Mandate that a Merchant, Credential Provider, and Merchant Payment Processor can verify and later present as dispute evidence [1]. It solves the "was this agent actually authorized to spend this money on this cart" problem for both human-present ("direct") and human-not-present ("autonomous") purchase flows, using two linked mandate types: a Checkout Mandate (what is being bought) and a Payment Mandate (how it is being paid for), each with a corresponding Receipt [1][4].

Overview

AP2 explicitly does not define a commerce protocol itself — no catalog APIs, no checkout session lifecycle, no merchant-facing REST surface — it is a security layer meant to sit inside a Commerce Protocol such as the Universal Commerce Protocol (UCP), which it says it is "designed explicitly to be compatible with" [1]. It also does not expose any discoverable endpoint or well-known file: mandates travel as message payloads inside whatever transport the surrounding commerce or agent-to-agent protocol uses, so there is no generic HTTP probe that proves or disproves AP2 support at an origin.

As of this verification, AP2's normative specification text has been donated by Google to the FIDO Alliance for continued stewardship; the original google-agentic-commerce/AP2 GitHub repository states explicitly that further contributions there are limited to code samples and an SDK, not the spec itself [2]. Google's original announcement (September 2025) cited more than 60 launch partners, though that figure comes from Google's own blog post rather than an independent count [3]. Reference samples exist in Python, Go, and Android using Google's Agent Development Kit (ADK) and Gemini models, but these are demonstration code, not a conformance suite.

What is disputed or unresolved: how governance actually operates now that the spec sits with FIDO rather than in the original GitHub repo — no FIDO-hosted specification page was located during this verification, only the original repository's copy and Google's donation announcement — and how the 60+ "launch partners" map to organizations actually running AP2-verified mandates in production versus organizations that merely endorsed the announcement.

Discovery and probe

No site-level discovery; AP2 mandates are exchanged as message payloads inside a Commerce Protocol (e.g. UCP) or an agent framework (A2A/MCP-compatible flows), not fetched from a well-known path · none

none none
parse:     not applicable — AP2 is a client-side/in-band mandate format, not an origin-exposed endpoint or file
on absent: There is no generic HTTP probe for AP2: a Merchant, Credential Provider, or Merchant Payment Processor supports AP2 only if it accepts and validates AP2 Checkout/Payment Mandates inside its own commerce protocol's message flow (e.g. as a UCP payment handler), which cannot be detected by an unauthenticated GET against the origin.

Not probed live: needs-credentials. AP2 mandates are exchanged inside an authorised checkout; nothing is published at a fixed path.

History

Instances

Every instance with its source is listed on the instances page.

See also

References

  1. AP2 defines five roles (Shopping Agent, Credential Provider, Merchant, Merchant Payment Processor, Trusted Surface) and two Mandate types (Checkout Mandate, Payment Mandate) used as cryptographic, signed evidence of what a user authorized, for both human-present and human-not-present flows; it is explicitly designed to be compatible with and complementary to UCP. — https://raw.githubusercontent.com/google-agentic-commerce/AP2/main/docs/ap2/specification.md VERIFIED
  2. AP2's CONTRIBUTING.md states the core specification has been donated to the FIDO Alliance, and that contributions to the google-agentic-commerce/AP2 repository going forward are to samples and SDK only. — https://raw.githubusercontent.com/google-agentic-commerce/AP2/main/CONTRIBUTING.md VERIFIED
  3. Google's launch announcement (blog.google / cloud.google.com) frames AP2 as an open protocol for agent payments with more than 60 partners at launch, and that the spec was donated to FIDO for continued development. — https://cloud.google.com/blog/products/ai-machine-learning/announcing-agents-to-payments-ap2-protocol (2025-09-16) REPORTED
  4. The AP2 checkout_mandate.md defines the Checkout Mandate as cryptographic proof to the Merchant that the Shopping Agent is authorized to purchase a specific Checkout, and a Checkout Receipt for the completed transaction. — https://raw.githubusercontent.com/google-agentic-commerce/AP2/main/docs/ap2/checkout_mandate.md VERIFIED

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