Definition
The Agentic Commerce Protocol (ACP) is an open standard, released under the Apache 2.0 license, that defines how buyers, their AI agents and businesses exchange product data and complete purchases. OpenAI and Stripe created it and remain its founding maintainers, and Meta has since joined its Technical Steering Committee. The specification is still labeled beta (ACP on GitHub).
ACP uses date-based versions, each a full snapshot of the spec. The first release was 2025-09-29, followed by snapshots adding fulfillment details (2025-12-12), capability negotiation (2026-01-16) and extensions, discounts and payment handlers (2026-01-30). The latest stable version, 2026-04-17, added carts, product feeds, orders, authentication and MCP support. Stripe's documentation groups the protocol into five building blocks:
- Agentic checkout: creating, updating and completing checkout sessions, with cart, fulfillment and payment details.
- Cart and feed: browsing product catalogs and managing carts before checkout.
- Delegated payment: passing payment tokens from buyer to merchant through the agent without exposing card details. Stripe was the first compatible payment provider, with its Shared Payment Token.
- Delegated authentication: letting an agent act for a buyer with a business through OAuth 2.0.
- Orders and webhooks: updates on confirmation, shipping, delivery and refunds.
ACP can be exposed as a REST API or through the Model Context Protocol. The business stays merchant of record and decides which agents and transactions to accept (agenticcommerce.dev).
Its history shows how quickly this area moves. ACP launched alongside Instant Checkout in ChatGPT in September 2025. OpenAI wound Instant Checkout down as a native feature in March 2026 and repositioned ACP as the infrastructure connecting merchants to ChatGPT across discovery: OpenAI's commerce docs tell merchants to start an ACP integration by sharing a structured product feed, and purchases now complete on merchant sites or in merchant apps inside ChatGPT. Meanwhile Stripe uses ACP to connect sellers to Microsoft's Copilot Checkout, launched in January 2026, and Stripe says ACP underpins a checkout flow inside Facebook ads it built with Meta. Public discovery of which merchants support ACP is still being worked out.
ACP sits beside several related standards rather than replacing them. Google's Universal Commerce Protocol (UCP), launched in January 2026, covers similar checkout ground for Google's AI surfaces. The Agent Payments Protocol handles signed proof that an agent is authorized to pay, and x402 handles HTTP-native payments. Our comparison of AP2, ACP and MCP explains how the layers fit.
For merchants, ACP is mostly reached through partners. Shopify and Etsy catalogs are already connected to ChatGPT, Stripe offers ACP support in its agentic commerce tools, and larger retailers can integrate directly. The practical starting point is the same as for any agentic commerce channel: a complete, current product feed with accurate prices, availability, variants and policies, because that feed now decides whether products appear in ChatGPT's shopping results at all (product feeds for AI shopping).
Examples of Agentic Commerce Protocol (ACP)
- A department store shares its catalog with OpenAI under the ACP feed specification, sending a full file nightly and price updates through the API, so its products appear accurately in ChatGPT shopping results.
- An Etsy seller is reachable in Copilot Checkout because Stripe connects Microsoft's checkout to sellers through ACP and issues a Shared Payment Token for each order.
- A developer building a shopping assistant implements the ACP checkout endpoints so the assistant can create and update checkout sessions with merchants that support the protocol, without becoming the merchant of record.
- A platform team reviews the 2026-04-17 snapshot to add cart and order webhook support before upgrading from the January 2026 version of the spec.
