AP2 (Agent Payments Protocol)
AP2 is an open protocol, started by Google, that lets an AI agent prove a person agreed to a purchase before it pays.
AP2, the Agent Payments Protocol, is an open standard for AI agents that pay for things. It gives the agent a way to prove that a person really did agree to a purchase, and to what limits, so the shop and the bank can trust the payment.
Google started it, and work on the standard now continues at the FIDO Alliance, the group behind passkeys. The AP2 site has the specification.
The problem it solves
When you pay online yourself, the shop and your bank have ways to check it's you. When an agent pays for you, that's harder. Did you ask for this? Did you agree to this price? Is the agent spending more than you allowed?
AP2 answers those questions with signed records called mandates. There are two kinds:
- A checkout mandate covers what's being bought: the items and the terms agreed with the merchant
- A payment mandate covers the money: which card or account to use, and how much
Each one can start open, with limits the person set, and end closed, tied to one finished order.
An example
Someone tells their assistant: "Reorder my usual beans from Kestrel Roasters when they're back in stock, as long as it's under £20." That instruction becomes an open mandate with a £20 limit. When the beans come back at £16, the agent builds the order, and the closed mandates record exactly what was bought and paid. If anything goes wrong, there's a record of what the person allowed.
How it fits with other standards
AP2 builds on A2A, which lets agents work with each other, and it can be used with MCP, which connects agents to tools. You'll also see it mentioned next to the Agentic Commerce Protocol, another open standard for agents that buy.
For most brands, this is work for your payments provider and your developers. What's worth knowing as a marketer is that agents buying on someone's behalf are being planned for in earnest.