What is the ACP (Agentic Commerce Protocol) from OpenAI and Stripe?

ACP stands for plenty of things. Here it is the Agentic Commerce Protocol, the way ChatGPT receives products from stores and, in some cases, processes the purchase. People search it by its full name more than by the acronym, and rightly so: it is how a merchant's catalog reaches ChatGPT's shopping answers. A store cares because it decides which data to provide and in what format.

How it works

The ACP is an open standard for purchase flows between buyers, AI agents and merchants, developed by Stripe and OpenAI under the Apache 2.0 license. It supports physical goods, digital goods, subscriptions and asynchronous purchases, offers REST endpoints and endpoints compatible with the MCP (Model Context Protocol), and keeps the merchant as the seller (the merchant of record).⁠^{[1]OpenAI and Stripe. Agentic Commerce Protocol} In OpenAI's documentation, the store sees three pieces:⁠^{[2]OpenAI Developers. Key concepts (Agentic Commerce)}

• The product feed. The merchant shares its product data with OpenAI, field by field, so ChatGPT can show it accurately in search and shopping.
• The checkout session. It is displayed inside ChatGPT, but the order state and the charge happen in the merchant's own systems, and the merchant accepts or rejects each order.
• The delegated payment. OpenAI securely passes the payment details to the merchant or its payment provider. OpenAI is not the seller: the merchant uses its own provider, as with any other digital payment.

The specification is published on GitHub with date-based versions. The first is from September 29, 2025; later came improvements to shipping, capability negotiation, extensions and discounts, and the current stable version, from April 17, 2026, adds cart, feed, orders, authentication and a link to MCP. OpenAI and Stripe are the founding maintainers, major changes go through formal proposals, and the repository labels the project as beta.⁠^{[3]OpenAI and Stripe, GitHub. agentic-commerce-protocol (specification repository)}

What has happened since 2025

OpenAI launched the ACP on September 29, 2025 alongside Instant Checkout: ChatGPT users in the United States could buy from US Etsy sellers without leaving the chat, one item at a time, with more than a million Shopify merchants announced as coming next. The merchant paid a small fee per completed purchase, and OpenAI said product results were organic and that offering Instant Checkout did not earn preference, although it counted as one more factor when ranking merchants that sell the same product.⁠^{[4]OpenAI. Buy it in ChatGPT: Instant Checkout and the Agentic Commerce Protocol}

On March 24, 2026 the focus shifted. OpenAI extended the ACP to product discovery: merchants share feeds and promotions, directly or through providers such as Salesforce and Stripe, and chains such as Target, Sephora, Nordstrom, Lowe's, Best Buy, The Home Depot and Wayfair were already integrated. Shopify stores arrive through Shopify Catalog with no extra work. And OpenAI acknowledged that the first version of Instant Checkout did not give it the flexibility it wanted, so it lets merchants use their own checkout process while it concentrates on discovery.⁠^{[5]OpenAI. Powering Product Discovery in ChatGPT}

Instant Checkout has not disappeared: the developer documentation says it is available to approved partners,⁠^{[2]OpenAI Developers. Key concepts (Agentic Commerce)} and the help center says ChatGPT may offer it for some eligible products and merchants.⁠^{[6]OpenAI, Help Center. Shopping with ChatGPT Search} Stripe, for its part, presents the ACP as one of the two protocols for selling through agents, alongside the UCP (Universal Commerce Protocol).⁠^{[7]Stripe, documentation. Agentic commerce}

In a store

The feed is the piece that touches every merchant. OpenAI asks for it in JSONL, one line per product or variant, with nine required fields: identifier, title, description, URL, brand, seller name, image, availability and price. It recommends titles of up to 150 characters and descriptions of up to 5,000, and warns that a row without a recognizable availability value is rejected.⁠^{[8]OpenAI Developers. Products (feed specification, Agentic Commerce)} Here is a product from a fictional example store, using the specification's fields:

{
  "item_id": "MOKA-INOX-6",
  "title": "Stainless steel stovetop espresso maker, 6 cups, induction-ready",
  "description": "18/10 stainless steel moka pot for 6 cups. Works on induction, gas and glass-ceramic stoves.",
  "url": "https://example-coffeemakers.com/products/moka-inox-6",
  "brand": "Example Brand",
  "seller_name": "Example Coffeemakers",
  "image_url": "https://example-coffeemakers.com/img/moka-inox-6.jpg",
  "price": "39.90 USD",
  "availability": "in_stock"
}

According to the specification, a product like this is enabled for search and disabled for checkout inside ChatGPT unless the merchant says otherwise, and being enabled does not guarantee it will be shown.⁠^{[8]OpenAI Developers. Products (feed specification, Agentic Commerce)} Clione builds that feed from the enriched catalog and uploads it every day to the SFTP account OpenAI gives the merchant; whether the products appear, and where, is up to OpenAI.

How to check

1. If you sell on Shopify, your products already reach ChatGPT through Shopify Catalog; check that each product's data in your admin is complete.⁠^{[5]OpenAI. Powering Product Discovery in ChatGPT}
2. If not, read the feed specification and request direct feed access from OpenAI's help center.⁠^{[6]OpenAI, Help Center. Shopping with ChatGPT Search}
3. Validate each row before sending it: the required fields, an allowed availability value and the price with its currency.⁠^{[8]OpenAI Developers. Products (feed specification, Agentic Commerce)}
4. Ask your provider which version it implements. The ACP changes through dated versions, and the stable one is the one from April 17, 2026.⁠^{[3]OpenAI and Stripe, GitHub. agentic-commerce-protocol (specification repository)}

Related concept: UCP

The UCP (Universal Commerce Protocol) solves the same problem from Google and Shopify: how an agent discovers, buys and tracks an order in a store. Both protocols keep the merchant as the seller and both can travel over MCP.⁠^{[1]OpenAI and Stripe. Agentic Commerce Protocol}⁠^{[9]Google, official blog. New tech and tools for retailers to succeed in an agentic shopping era} What differs, in practice, is where they are used: the ACP feeds ChatGPT; the UCP feeds Google's AI Mode and Gemini. Stripe supports both for selling through agents,⁠^{[7]Stripe, documentation. Agentic commerce} so for many stores it is not an either-or choice.

To go further, agentic commerce separates discovering, recommending and buying, and the agentic commerce reading path lays out the rest of the protocols.