What is the Agentic Commerce Protocol (ACP)?
Last verified 2026-06-10The Agentic Commerce Protocol (ACP) is an open standard, co-developed by OpenAI and Stripe and announced on 29 September 2025, that lets AI agents complete purchases with businesses. It powers Instant Checkout in ChatGPT, starting with Etsy sellers and, soon, Shopify merchants. The merchant stays the merchant of record and keeps its existing payment processor; orders flow from the agent to the merchant backend over the protocol. ACP is licensed under Apache 2.0 and maintained on GitHub by OpenAI and Stripe (currently beta). Stripe merchants can enable agentic payments in as little as one line of code using a Shared Payment Token.
Key facts
| Author / steward | OpenAI and Stripe |
|---|---|
| Announced | 2025-09-29 |
| License | Apache 2.0 |
| Governance | Founding maintainers OpenAI and Stripe, with a stated path toward broader community governance |
| Scope | Open standard connecting buyers, their AI agents and merchants to complete a purchase; powers Instant Checkout in ChatGPT, with the merchant remaining merchant of record |
| Transport | HTTP (OpenAPI/JSON Schema); MCP support added in the 2026-04-17 spec |
| Payment | Delegated Payments Spec; Stripe Shared Payment Token (SPT) for agent-initiated payments without exposing credentials |
| Maturity | beta |
What makes it distinctive
- Co-developed by Stripe and OpenAI, announced 29 September 2025
- Open source under Apache 2.0, spec maintained on GitHub by OpenAI and Stripe
- Powers Instant Checkout in ChatGPT (Etsy, then Shopify merchants)
- Merchant stays merchant of record; works with existing payment processors
- One-line enablement for existing Stripe merchants via Shared Payment Token
How ACP works
ACP is an interaction model between three parties: the buyer, the buyer’s AI agent, and the business. The agent surface (ChatGPT in the reference implementation) presents products; when the buyer decides to purchase, the order flows over ACP from the agent to the merchant’s backend. The merchant accepts or declines, charges the payment method, calculates tax and handles fulfillment and returns exactly as it would for any other order. Two machine-readable specs anchor the protocol: the Agentic Checkout spec (the checkout session lifecycle) and the Delegate Payment spec (how a payment credential is passed without exposing it). On the payment side, Stripe’s Shared Payment Token (SPT) scopes a credential to a specific merchant and cart total, which is how an existing Stripe merchant can enable agentic payments with a one-line change.
Specification, versions and governance
The specification lives on GitHub under agentic-commerce-protocol (Apache 2.0) and uses date-based versioning. Five versions have shipped: 2025-09-29 (initial release), 2025-12-12 (fulfillment enhancements), 2026-01-16 (capability negotiation), 2026-01-30 (extensions, discounts, payment handlers) and 2026-04-17 (cart, feed, orders, authentication and MCP support). Each version ships OpenAPI YAML, JSON Schemas and examples. RFCs cover agentic checkout, capability negotiation, payment handlers, seller-backed payment handlers, extensions and a discount extension. Governance is consensus-based between the founding maintainers OpenAI and Stripe, contributions require a CLA, and the project states a path toward neutral foundation stewardship as the ecosystem matures.
How ACP fits the stack
ACP is the checkout layer attached to the ChatGPT surface. It does not replace the context layer (MCP): since the 2026-04-17 version, ACP can run over MCP as a transport. It overlaps with UCP on agent checkout but the two are attached to different surfaces (ChatGPT vs Google AI Mode and Gemini); a merchant can implement both (ACP vs UCP). AP2 addresses payment authorization across networks rather than a single checkout flow (ACP vs AP2), and Visa’s TAP is positioned by Visa as complementary to ACP for agent verification.
Limitations and open questions
ACP is in beta. Instant Checkout launched for US ChatGPT users with US Etsy sellers, with Shopify merchants announced as coming next (announcement of 29 September 2025; current merchant coverage should be checked against OpenAI’s documentation). Governance remains with the two founding maintainers for now, and the protocol’s reach is tied to ChatGPT’s commerce footprint. Specifics such as category coverage, geographic expansion and the cadence of merchant onboarding are not published in the spec itself.
Who should care
Merchants that want to sell inside ChatGPT, starting with those already on Stripe (lowest integration cost). PSPs, who can implement the Delegate Payment spec. Agent builders, who get a documented checkout lifecycle with examples. See how to accept payments from AI agents.