Agentic Commerce Protocol (ACP)

The Agentic Commerce Protocol (ACP) is an open standard, developed by OpenAI and Stripe and first released on 29 September 2025, that defines how AI agents, buyers and businesses exchange the information needed to complete a purchase. It gives merchants one interface for selling through AI agents, covering the checkout session, the hand-off of payment credentials and the product data that agents read.

ACP launched alongside Instant Checkout in ChatGPT, its first implementation, and is published under the Apache 2.0 licence. It is one of several protocols for agentic commerce and is often compared with Google's Agent Payments Protocol (AP2). ACP concentrates on the merchant's checkout and on passing a limited payment token, while AP2 centres on signed records of what the user authorised.

Picture a restaurant that takes orders from a delivery app. The app does not walk into the kitchen and cook; it sends a standard order slip the kitchen understands, and the restaurant decides whether to accept it, cooks the meal and stays responsible for it. ACP is that order slip for online shopping, written so that an AI assistant can fill it in for a customer.

Payment works like a one-time voucher. Instead of handing the assistant your card, your payment provider gives it a voucher that can only be spent at one shop, up to one amount. The shop cashes the voucher through its usual payment company. The assistant never holds your full card number, and the shop keeps its own customer relationship.

OpenAI and Stripe announced ACP on 29 September 2025, when ChatGPT users in the United States could buy single items from US Etsy sellers without leaving the chat, with more than a million Shopify merchants named as coming later. On 28 October 2025 PayPal said it would adopt ACP so that its merchants could be found and paid in ChatGPT from 2026. The specification uses dated versions, published after the first release on 12 December 2025, 16 January 2026, 30 January 2026 and 17 April 2026, adding fulfilment details, capability negotiation, extensions and discounts, and later carts, orders, authentication and support for the Model Context Protocol.

In March 2026 OpenAI said Instant Checkout was moving into merchants' own apps within ChatGPT and that it would focus on search and product discovery, with ACP remaining the infrastructure connecting users to merchants. The protocol was still marked as beta in November 2026, maintained jointly by OpenAI and Stripe with a stated aim of moving to neutral stewardship.

ACP is a set of API specifications that can run over ordinary REST calls or the Model Context Protocol. Its main parts are:

• Product feed. The merchant shares structured product data, such as titles, prices, stock and images, so the agent can find and display items accurately.
• Agentic checkout. The agent opens a checkout session with the merchant, updates it with items, shipping address and delivery option, and receives the merchant's totals, taxes and status, before completing or cancelling the order.
• Delegated payment. A payment service provider turns the buyer's payment details into a scoped token that the agent passes to the merchant. Stripe's version is the Shared Payment Token, limited to one merchant and one cart total.

The merchant remains the merchant of record. It accepts or declines each order, charges the payment method through its chosen payment processor, calculates tax and handles fulfilment and returns. Stripe said merchants need not process through Stripe, and that those using other providers could still use its fraud signals.

The delegated payment design applies tokenization to agent purchases. The token carries limits on merchant, amount and expiry, so a leaked token is of little use elsewhere, and the raw card number never reaches the AI platform. Card payments still travel over the existing card networks as card-not-present transactions, with normal authorisation and settlement. Disputes and chargebacks follow the merchant's usual processes, because the merchant took the order.

Unlike AP2, early ACP versions did not require a separate cryptographically signed record of the user's intent, an agentic mandate. The scoped token, together with the user confirming the purchase in the chat, served as the evidence of consent; the April 2026 version added authentication features.

Merchants, e-commerce platforms and processors increasingly support several of these at once, since each AI platform has backed a different standard.

• Agentic Commerce Protocol
• Agentic Commerce Protocol specification on GitHub
• OpenAI: Agentic Commerce developer documentation