🦾 Agentic Commerce

Agent Payments Protocol

ap2 · agent payments protocol · agent payment protocol · google ap2 · agentic payments protocol · intent mandate · cart mandate

Definition

AP2 is Google's open protocol for agent payments. It uses cryptographically signed intent and cart mandates so that a purchase made by an AI agent is provably authorised.

The problem AP2 solves

When an AI agent buys something on a user’s behalf, three questions appear:

Authorisation: did the agent have the right to make this purchase?
Authenticity: was the agent really acting on a specific user’s instruction?
Liability: who is responsible in a dispute — the user, the agent or the platform?

Existing payment protocols were never designed for a purchase that a human does not initiate. AP2 is
Google’s answer to that gap.

Architecture: two mandates

AP2 uses a two-layer system of cryptographically signed documents.

Intent Mandate — issued by the user to the agent in advance:

{
  "authorized_categories": ["electronics", "books"],
  "max_price": 200,
  "currency": "USD",
  "valid_until": "2025-12-31",
  "signature": "<user_private_key>"
}

Cart Mandate — produced by the agent at the moment of a specific purchase:

{
  "items": [...],
  "total": 115,
  "merchant": "re:Store",
  "delivery_date": "2025-06-05",
  "intent_mandate_ref": "<hash>",
  "signature": "<agent_key>"
}

The payment system checks both mandates: if the Cart Mandate stays inside the limits of the Intent
Mandate, the transaction is authorised.

Where AP2 sits among agent protocols

AP2 extends A2A (Agent2Agent), Google’s base protocol for interaction between agents. Where MCP
(Anthropic’s Model Context Protocol) solves the problem of connecting agents to tools and data, AP2
solves the problem of financial transactions with provable consent.

Protocol	Problem it solves
MCP	Agent ↔ tools and data
A2A	Agent ↔ agent
AP2	Agent ↔ payment system, with a mandate
ACP	A broad agentic commerce standard

What this means for retailers

Support for AP2 on the payment gateway side is the condition for receiving orders from autonomous
agents. Without it, the agent either cannot complete the transaction at all or has to fall back on
manual confirmation from the user, which removes most of the value of autonomy.

Important: AP2 is an open protocol under active development. What matters for a retailer is
tracking its adoption by payment providers — gateway-level implementation arrives before
store-level integration does.

Frequently asked questions

How does AP2 differ from an ordinary tokenised payment?

A conventional token authorises the payment at the moment of the transaction. AP2 introduces two layers of authorisation: the user signs an Intent Mandate in advance (permission for a class of purchases), and the agent produces a Cart Mandate for the specific purchase (exact items, exact price). The payment system verifies both signatures, which makes the transaction provably authorised without the user being present at the moment of purchase.

Who already supports AP2?

As of mid-2025, Visa, Mastercard and a number of payment providers had announced support. The protocol is open, so banks, payment gateways and trading platforms can all implement it.

What are an Intent Mandate and a Cart Mandate?

An Intent Mandate is a cryptographically signed permission from the user: I allow the agent to buy items from category X up to Y dollars. A Cart Mandate is the agent's signature fixing one specific basket: items, prices, merchant, delivery terms. Both mandates travel to the payment system with the transaction.