Agent Payments Protocol (AP2)

AP2 is built on mandates, which Google's launch post calls tamper-proof digital contracts signed with verifiable credentials. The first version had an Intent Mandate, which holds the request and its limits, and a Cart Mandate, which holds the exact items and price the customer approved. The current specification on ap2-protocol.org uses a Checkout Mandate for the merchant and a Payment Mandate for the credential provider, the card network and the merchant's processor, each in an open form with limits and a closed form for one finished checkout.

Two cases are covered. With the customer present, the customer approves the cart and signs the mandate in real time. With the customer absent, the customer signs the limits in advance, for example a maximum price, and the agent completes the purchase once the conditions are met. The chain of signed mandates gives an audit trail that a bank can use in a dispute.

Google launched AP2 with more than 60 organizations, among them Adyen, American Express, Mastercard, PayPal, Revolut, Worldpay and Coinbase. With Coinbase, the Ethereum Foundation and MetaMask, Google built an extension that carries AP2 mandates into x402 stablecoin payments.

Google later handed AP2 to the FIDO Alliance, the body behind passkeys. PYMNTS reports that the alliance set up an Agentic Authentication Technical Working Group and a Payments Technical Working Group, which build on AP2 and on Mastercard's Verifiable Intent framework.

The protocol is payment-method agnostic: Google names cards, stablecoins and real-time bank transfers. The specification starts with card payments that the merchant pulls; push payments such as instant credit transfers and digital currencies are on its roadmap. For European banks that matters, because SEPA Instant and account-to-account payments are push payments.

A mandate does not replace strong customer authentication under PSD2. It documents what the customer agreed to, and the bank still decides how the payment is authenticated. With AP2 in the FIDO Alliance, the mandate and the passkey are now specified in the same body; Visa already confirms agent payments in Europe with passkeys.

AP2 is an open protocol for payments that an AI agent starts on a customer's behalf. Signed mandates record what the customer asked for and approved, so every party in the payment can verify it.

AP2 is an extension of the Agent2Agent protocol (A2A), Google's protocol for agents that talk to other agents, and it can be used next to the Model Context Protocol, which connects an agent to tools and data. The MCP page covers MCP servers of banks and data providers.

No. x402 is a way for a server to ask for a payment inside a web request, mostly in stablecoins. AP2 records the customer's consent and works with several payment methods; an AP2 extension uses x402 for the stablecoin case.