What is AP2 (Agent Payments Protocol)?

AP2 stands for Agent Payments Protocol, the payments protocol for agents that Google introduced. It matters for a very store-shaped reason: when whoever clicks "pay" is an AI agent and not a person, the store needs to know someone authorized that purchase, because if the charge is disputed, someone will have to prove it. AP2 is Google's proposal, built with its partners, for carrying that proof along with the order.

How it works

Google introduced it on September 16, 2025 as an open protocol, developed with payments and technology companies, for starting and completing agent-led payments across different platforms, with more than 60 organizations collaborating, among them Adyen, American Express, Mastercard, PayPal, Revolut and Worldpay.⁠^{[1]Google Cloud Blog (Stavan Parikh and Rao Surapaneni, September 16, 2025). Announcing Agent Payments Protocol (AP2)} Its official site now describes it as an extension of the A2A and UCP (Universal Commerce Protocol) protocols.⁠^{[2]AP2, official protocol site. Agent Payments Protocol (AP2)}

The v0.2 specification splits the work across five roles:⁠^{[3]AP2, official protocol site. Agent Payments Protocol Specification (v0.2)}

• The Shopping Agent: finds products, builds the cart and runs the purchase.
• The Credential Provider: the source of the payment details, which checks that the agent is authorized.
• The Merchant: prepares and closes the order, and checks that the agent has permission to buy those items.
• The Merchant Payment Processor: processes the charge and verifies the credential's authorization.
• The Trusted Surface: the screen where the person gives consent. The specification requires that it not be agentic.

The central piece is the mandates, signed records of what the person authorized (the AP2 mandate has its own entry). In v0.2 there are two: the checkout mandate, which proves to the store that the agent may buy that cart, and the payment mandate, which proves to the credential provider, the network and the processor that it may pay for it.⁠^{[3]AP2, official protocol site. Agent Payments Protocol Specification (v0.2)} Each can be open, when it captures the conditions the person sets before any cart exists, or closed, when it authorizes one specific order and amount.⁠^{[2]AP2, official protocol site. Agent Payments Protocol (AP2)} Mandates are signed as SD-JWT, a credential format that lets you reveal only part of the data.⁠^{[3]AP2, official protocol site. Agent Payments Protocol Specification (v0.2)}

With those pieces, AP2 describes two ways to buy:⁠^{[4]AP2, official protocol site. Flows}

1. With the person present (Human Present): the person sees the finished order and approves the checkout and the payment directly, for example with a fingerprint.
2. Without the person present (Human Not Present): the person first signs open mandates with their limits and walks away. The agent, on its own, builds an order that meets those conditions and signs the closed mandates itself. This is what is called delegated payments.

If the store or the credential provider sees that the order does not fit the signed conditions, they can return an unresolved-constraint error and force the person to approve it again.⁠^{[4]AP2, official protocol site. Flows}

What is available and what is only announced

The protocol moves fast, and its own documents have changed from one version to the next. This is where things stand as of October 6, 2026:

Watch the payment methods. The 2025 announcement said AP2 supported different payment types, from credit and debit cards to stablecoins and instant transfers.⁠^{[1]Google Cloud Blog (Stavan Parikh and Rao Surapaneni, September 16, 2025). Announcing Agent Payments Protocol (AP2)} The official site, which is more recent, is more precise: the initial version supports "pull" payments such as cards, and the rest is on the roadmap.⁠^{[2]AP2, official protocol site. Agent Payments Protocol (AP2)} When two texts from the same owner disagree, the newer one wins. The FIDO Alliance, for its part, says it is already working on those groups and will report as it progresses, with no dates.⁠^{[7]FIDO Alliance (April 28, 2026). FIDO Alliance to develop standards for trusted AI agent interactions}

In a store

A fictitious example of the flow without the person present, in a coffee shop. The customer tells her agent: "Buy a kilo of Ethiopian whole-bean coffee when it drops below 30 dollars." Step by step, following the flows AP2 publishes:⁠^{[4]AP2, official protocol site. Flows}

For the store, the new work is in steps 3 and 6: signing the order and checking that the mandate matches that cart before charging. The agent and the payment intermediaries do the rest.

How to check it

1. Open the specification and look at the version. As of October 6, 2026 it is v0.2; if you see another, what this page says may have changed.⁠^{[3]AP2, official protocol site. Agent Payments Protocol Specification (v0.2)}
2. Check the versions published on GitHub, with their dates: the changelog tells you whether a new feature is already code or only intent.⁠^{[5]GitHub, official AP2 repository. Releases · google-agentic-commerce/AP2}
3. Check which payment methods the current version covers on the official site before assuming your favorite method is in.⁠^{[2]AP2, official protocol site. Agent Payments Protocol (AP2)}
4. If you sell to the United States, look at your Google Merchant Center account. It is Google's requirement for products to enter the UCP reference checkout, in AI Mode and in the Gemini app.⁠^{[6]Google for Developers Blog (January 11, 2026). Under the hood: Universal Commerce Protocol (UCP)}
5. Ask your platform and your gateway whether they accept orders with AP2 mandates and since when. The answer tells you whether this is your concern or theirs.

Related concept: UCP

UCP and AP2 get cited together and do different things. UCP is an open-source standard for agentic commerce that today moves the checkout between an agent and the store, also supports identity linking and order management, and integrates through an API, A2A or MCP.⁠^{[6]Google for Developers Blog (January 11, 2026). Under the hood: Universal Commerce Protocol (UCP)} AP2 handles only the payment part: UCP says what is bought and how; AP2 proves the person authorized it. Google sums it up when introducing UCP: it is compatible with AP2 to support secure agent payments.⁠^{[6]Google for Developers Blog (January 11, 2026). Under the hood: Universal Commerce Protocol (UCP)} The ACP (Agentic Commerce Protocol) is another shopping protocol proposal, with its own entry.

To keep going, the agentic commerce reading path orders these protocols and the rest of the vocabulary.