When was AP2 announced?

Google announced it in September 2025. Version 0.2 was released and donated to the FIDO Alliance on 28 April 2026, moving governance out of a single vendor and into a neutral standards body.

Does AP2 replace 3D Secure?

They address different situations. 3D Secure authenticates a cardholder who is present during a transaction; AP2 establishes that a human authorized an agent to transact later, on their behalf, within stated limits — the case that has no good existing answer.

Do I need AP2 to accept agent-initiated payments?

Not today, and you largely cannot adopt it alone — it requires your processor and the issuing side to participate. The practical step is asking your payment provider about their timeline and weighing the answer when choosing a processor.

Why does agent-initiated payment authorization need a new protocol?

Because existing evidence formats assume a human was present at the transaction. When a purchase is disputed and the cardholder says an AI made it, a merchant needs a verifiable artifact proving what was authorized and within what limits — which is precisely what a signed mandate provides and a receipt does not.

Agentic commerce

What is AP2, the Agent Payments Protocol?

Updated August 14, 2026

AP2 — the Agent Payments Protocol — uses verifiable digital credentials and cryptographic mandates to prove that a specific human authorized a specific agent-initiated purchase, within limits they set. Announced by Google in September 2025, it addresses the question the commerce protocols leave open: how anyone later establishes that the cardholder actually consented. Google released v0.2 and donated the protocol to the FIDO Alliance on 28 April 2026, moving it out of single-vendor control.

The problem AP2 exists to solve

Every other protocol in this space assumes the purchase is authorized and describes how it executes. None of them answers the question that decides whether a merchant can safely accept agent-initiated payments at scale: when a charge is disputed months later, how do you demonstrate the cardholder consented to this purchase, at this amount, through this agent?

Without an answer, agent-initiated payments are a dispute liability wearing a growth-channel costume. "An AI bought it on my behalf" is a sympathetic story for a cardholder to tell their issuer and a difficult one for a merchant to rebut with the evidence formats that exist today.

AP2 makes consent cryptographic and portable. A mandate signed by the human establishes what was authorized, and that artifact is verifiable by parties who were not present when it was created.

Why the FIDO donation is the important event

Google released v0.2 and donated AP2 to the FIDO Alliance on 28 April 2026. That governance change matters considerably more than the version increment.

A payment-authorization standard controlled by one company is a standard every other company has a structural reason to resist, particularly when that company also operates a competing assistant and an advertising business. Issuers and processors have to adopt it for it to mean anything, and they are not inclined to adopt a competitor's specification.

FIDO is a neutral standards body with an established track record in authentication — the organisation behind the passkey and WebAuthn work that issuers and platforms already implement. Moving AP2 there makes broad adoption plausible in a way it was not while it sat with a single sponsor.

Where it sits relative to the other protocols

It is the last layer, and deliberately so.

Question	Answered by
What tools can this agent call?	MCP
What do you sell, and what does a cart cost?	UCP
How does the purchase execute in the AI interface?	ACP
Who authorized this payment, and for how much?	AP2

AP2 in the stack

What a merchant should do about it today

Very little, and that is the correct answer rather than a cop-out.

AP2 is the layer still furthest from settled and the one you least want to build twice. It also cannot be adopted unilaterally — it requires your processor and the issuing side to participate, so a merchant implementing ahead of their processor has built something with nothing to talk to.

The useful action is to ask your payment provider what their AP2 timeline is, and to treat the answer as a real input when choosing a processor. Beyond that, the general dispute hygiene that helps here is the same as it has always been: assemble evidence at transaction time rather than at dispute time, because representment is lost to deadlines far more often than to the merits.

Frequently asked questions

When was AP2 announced?: Google announced it in September 2025. Version 0.2 was released and donated to the FIDO Alliance on 28 April 2026, moving governance out of a single vendor and into a neutral standards body.
Does AP2 replace 3D Secure?: They address different situations. 3D Secure authenticates a cardholder who is present during a transaction; AP2 establishes that a human authorized an agent to transact later, on their behalf, within stated limits — the case that has no good existing answer.
Do I need AP2 to accept agent-initiated payments?: Not today, and you largely cannot adopt it alone — it requires your processor and the issuing side to participate. The practical step is asking your payment provider about their timeline and weighing the answer when choosing a processor.
Why does agent-initiated payment authorization need a new protocol?: Because existing evidence formats assume a human was present at the transaction. When a purchase is disputed and the cardholder says an AI made it, a merchant needs a verifiable artifact proving what was authorized and within what limits — which is precisely what a signed mandate provides and a receipt does not.

Sources

Agentic commerce standards: UCP vs ACP vs AP2 — merchant guide — Digital Applied
MCP vs A2A vs ACP vs AP2: agentic commerce protocols compared — Cipher Projects