The Agentic Commerce Protocol started life as the plumbing behind ChatGPT Instant Checkout. When OpenAI retired native checkout in March 2026, ACP survived and changed job. It is now mainly how merchants hand ChatGPT their product catalogs so ChatGPT can recommend them. This tracker covers who is on it, what the spec now includes, and what that means for brands that are not.
What ACP Is
ACP is an open standard, licensed under Apache 2.0, co-developed and maintained by OpenAI and Stripe. The spec repository lists it as beta. OpenAI's documentation splits it into three parts: product feeds that merchants send to ChatGPT, agentic checkout endpoints merchants can implement, and delegated payment handled by payment service providers so the agent never holds raw card details.
Spec Versions
| Version | What changed |
|---|---|
| 2025-09-29 | Initial release alongside Instant Checkout |
| 2025-12-12 | Fulfillment enhancements |
| 2026-01-16 | Capability negotiation |
| 2026-01-30 | Extensions, discounts, payment handlers |
| 2026-04-17 | Cart, feed, orders, authentication, and MCP support (latest stable) |
The April release matters most for this tracker. Adding cart and feed objects formalised the discovery role ACP took on after March, and MCP support means an ACP merchant can be reached by agents outside ChatGPT that speak Anthropic's Model Context Protocol.
Who Is on ACP
| Participant | Role | Status, September 2026 |
|---|---|---|
| Target, Sephora, Nordstrom, Lowe's, Best Buy, The Home Depot, Wayfair | Product discovery feeds in ChatGPT | Named by OpenAI at the March 24 relaunch |
| Shopify merchants | Catalog data via Shopify Catalog and Agentic Storefronts | On by default for eligible stores since March 24 |
| Etsy | Original Instant Checkout partner | Moved to discovery plus a ChatGPT app |
| Walmart | ChatGPT app with account linking, loyalty, Walmart payments | Live on web at launch, with iOS and Android announced |
| Stripe | Co-maintainer, delegated payment via Shared Payment Tokens | Live |
| PayPal | ACP-compatible payment provider | Announced October 2025 |
Two things stand out. First, the named discovery retailers skew toward big-box and specialty chains with mature feed operations, because ACP rewards clean, frequently refreshed catalog data. Second, most of the long tail is on ACP indirectly, through Shopify, rather than through its own integration.
How Feeds Work
Merchants supply a structured product feed through an API or an SFTP file upload. Third-party guides describe compressed JSON Lines or CSV files refreshed as often as every 15 minutes. Frequency matters because stale price and stock data was one of the problems that sank Instant Checkout. A feed that disagrees with the product page is the fastest way to lose ChatGPT's trust in a listing.
ACP Versus UCP
ACP is OpenAI and Stripe's standard. The Universal Commerce Protocol is Google and Shopify's, launched at NRF in January 2026. Large retailers increasingly support both, and Shopify merchants get both through the platform. The practical split is that ACP decides what ChatGPT can see, and UCP decides what Google AI Mode, Gemini, and other UCP agents can see and buy. See UCP vs ACP vs AP2.
Brand Visibility Implications
An ACP feed does not guarantee a recommendation, but a missing or stale feed nearly guarantees you are left out of product carousels for anything more specific than your brand name. For brands not on Shopify and not among the named retailers, the gap is real: ChatGPT falls back to what it can crawl and what third parties say about you. Check whether your products appear in ChatGPT shopping answers before assuming you are covered by a reseller's feed, because the reseller's listing, not yours, is what gets the click.
Methodology
Figures on this page come from primary sources wherever one exists: company announcements, developer documentation, and earnings materials, including OpenAI's commerce documentation, the ACP specification repository, Shopify's Spring '26 developer release, Shopify's agent profile docs, and Amazon's Q4 2025 earnings release. Where only trade press reports a figure, such as retailer conversion comparisons from Modern Retail or Digital Commerce 360, the page says so. Where sources disagree, a range is given. Status as of September 2026.
How Presenc AI Helps
Presenc AI measures how often your products appear in ChatGPT shopping answers, whether the link goes to your store or a reseller, and whether prices and availability shown in the answer match your site.