The Agentic Commerce Protocol (ACP) is the open standard — co-developed by OpenAI and Stripe, open-sourced in February 2026 under Apache 2.0 — that defines how AI agents discover products, build carts, and complete purchases on behalf of users. It is already in production: ChatGPT users can shop from PayPal, Worldpay, and Checkout.com merchants without leaving the conversation.
Note on naming: This is a different protocol from the Agent Client Protocol (ACP), which standardises editor-to-agent communication. Same acronym, different problem domain.
The Problem It Solves
Before ACP, every AI shopping integration required bespoke work: a custom chatbot plugin, a proprietary checkout flow, a one-off API contract between an AI platform and a merchant. ACP defines a standard interaction model so that any AI agent can discover any merchant's catalogue, construct a cart, and trigger checkout — without custom integration on either side.
How It Works
ACP defines a structured message exchange between three parties:
User ──► AI Agent ──► ACP Server (merchant/PSP) ──► Payment Rails
│ │
└── intent/cart ─────┘
mandates
- Discovery — The agent queries an ACP-compatible server to browse products and check availability
- Cart construction — The agent builds a cart from structured product data returned by the server
- Checkout — The agent submits a signed cart and the server returns a payment confirmation or a hosted checkout URL for the user to complete
For human-not-present flows (delegated purchasing), ACP relies on a signed Intent Mandate scoped with price limits and allowed categories — similar in concept to OAuth scopes, but for spending authority.
Who Supports It
As of March 2026, ACP has production or committed support from:
| Organisation | Role |
|---|---|
| OpenAI | Co-author, reference implementation in ChatGPT |
| Stripe | Co-author, reference PSP integration |
| PayPal | Live in ChatGPT Instant Checkout (announced October 2025) |
| Worldpay | Live for US merchants (announced October 2025) |
| Checkout.com | Committed |
| Worldline | Committed |
| FIS / Spreedly / Mollie / Nexi | Committed |
| Visa | Aligning Trusted Agent Protocol with ACP |
It is governed by the Agentic AI Foundation (AAIF) — the Linux Foundation body co-founded by Anthropic, OpenAI, and Block — giving it the same neutral stewardship as MCP.
Relationship to Other Payment Protocols
ACP, AP2, and x402 address different layers of the agentic payments stack:
| Protocol | Layer | Author | Focus |
|---|---|---|---|
| ACP | Commerce / checkout | OpenAI + Stripe | Merchant discovery, cart, checkout UX |
| AP2 | Trust / authorisation | Cryptographic mandates, W3C Verifiable Credentials | |
| x402 | Execution / micropayments | Coinbase + Cloudflare | HTTP-native, stablecoin, per-call payments |
These are complementary rather than competing — a production agentic commerce system might use ACP for merchant integration, AP2 for the trust model, and x402 for agent-to-API micropayments.
Why Trial, Not Adopt
For Trial:
- Production deployments exist and are live in ChatGPT for millions of users
- AAIF governance provides neutral, long-term stewardship
- Broad PSP adoption (Stripe, PayPal, Worldpay, Checkout.com, FIS) eliminates the "only works with one processor" concern
- Open-sourced under Apache 2.0 — no proprietary lock-in
Why not Adopt:
- Spec is still pre-1.0 as of March 2026 — breaking changes expected
- Delegated / human-not-present purchasing is still nascent; trust models and liability frameworks remain unsettled
- Currently ChatGPT-centric; Claude, Gemini, and open-source agent integration is in progress
- Not all PSPs have shipped — committed is not the same as available
Key Characteristics
| Property | Value |
|---|---|
| Co-authors | OpenAI, Stripe |
| Governance | Agentic AI Foundation (Linux Foundation) |
| License | Apache 2.0 |
| Open-sourced | February 2026 |
| GitHub | agentic-commerce-protocol/agentic-commerce-protocol |
| Related | AP2, x402, Stripe Agent Toolkit, Worldpay MCP |