Payment layer
AP2: the protocol that authorizes an agent to pay.
The Agent Payments Protocol (AP2) standardizes the authorization of payments initiated by AI agents, via cryptographic mandates. Here are its principles, governance, and place in the agentic commerce stack.
The 30-second summary
- What: an open protocol to authorize payments triggered by agents.
- How: three signed mandates (intent, cart, payment).
- Who: initiated by Google (Sept. 2025), governance handed to the FIDO Alliance, 120+ partners.
- Place: the authorization layer, compatible with UCP, A2A and MCP; x402 for stablecoin settlement.
A short definition
AP2 (Agent Payments Protocol) is an open protocol that standardizes how a payment triggered by an agent is authorized. Instead of sharing a card number, the agent presents a cryptographically signed proof of authorization. AP2 is the "authorization" building block of the agentic payment layer. Established
The three mandates
AP2 breaks consent into three signed proofs that form an auditable chain:
- Intent mandate: what the user wants to accomplish (e.g. re-buy a product under a certain price).
- Cart mandate: the exact items, price and terms the user commits to.
- Payment mandate: the final settlement authorization.
This separation makes it possible to prove, after the fact, who authorized what and within which limits, which is the hard part of any delegated payment. Established
Governance and adoption
Initiated by Google in September 2025, AP2 had its governance handed to the FIDO Alliance and now claims 120+ partners, including PayPal and its PYUSD stablecoin. Moving under an independent standards body signals maturation of the authorization layer, even if production adoption is still emerging. Emerging
AP2 in the agentic stack
AP2 does not work alone. It combines with the other protocols in the stack:
- UCP and ACP: commerce operations (catalog, cart, checkout). See UCP vs ACP.
- A2A: agent-to-agent communication (stewarded by the Linux Foundation).
- MCP: agents' access to tools and data.
- x402: an AP2-linked extension, backed by Coinbase, for machine-to-machine stablecoin settlement.
UCP is explicitly designed to be compatible with AP2: a merchant preparing its offer for agents builds shared groundwork, whatever the authorization protocol. Established
What it changes for a merchant
For a merchant, AP2 is mainly a trust-and-compliance guarantee: authorization is proven and traceable, and the merchant remains the seller of record. The work to do is the same as for agentic commerce: a machine-readable offer and clear governance. The audit methodology helps assess that state.
Frequently asked questions
01 What is AP2?
What is AP2?
AP2 (Agent Payments Protocol) is an open protocol, initiated by Google in September 2025, that standardizes the authorization of payments triggered by AI agents. It relies on cryptographically signed mandates that prove the user's consent.
02 What are AP2's three mandates?
What are AP2's three mandates?
AP2 defines three signed proofs: the intent mandate (what the user wants), the cart mandate (the items and price they commit to) and the payment mandate (the final settlement authorization). This chain makes the transaction auditably user-authorized.
03 Who governs AP2?
Who governs AP2?
AP2's governance was handed to the FIDO Alliance, and the protocol claims 120+ partners, including PayPal (with its PYUSD stablecoin). It signals that the agentic payment-authorization layer is being organized at the standards level.
04 Does AP2 replace UCP or ACP?
Does AP2 replace UCP or ACP?
No. AP2 covers payment authorization. UCP and ACP structure commerce operations (catalog, cart, checkout). A2A handles agent-to-agent communication, MCP handles tool access. These protocols stack rather than compete: UCP is designed to be compatible with AP2.
Primary sources
- ap2-protocol.org: protocol site.
- AP2 specification (GitHub).
- FIDO Alliance: governance body.
Go further