Glossary
Agentic Commerce Protocol (ACP): What It Is and How to Use It
Definition
The Agentic Commerce Protocol (ACP) is an open specification from OpenAI and Stripe for how AI agents and merchants exchange product, checkout and payment information. It launched in September 2025 to power Instant Checkout in ChatGPT. Since March 2026 OpenAI uses it mainly for product discovery, with most purchases completed on merchants’ own checkouts. It is a spec, not a product, and adoption runs through commerce platforms.
Also called: ACP, OpenAI commerce protocol
At a glance
- CategoriesCommerce
- Related fieldsCommerce, Technical
- DifficultyIntermediate
At a glance
- ACP is published openly, with the specification and reference material at agenticcommerce.dev.
- Stripe and OpenAI released it in September 2025 alongside Instant Checkout in ChatGPT, its first live implementation.
- In March 2026 OpenAI refocused it on product discovery and moved most purchases to merchants’ own checkouts.
- The merchant stays the seller of record and keeps pricing, tax, stock and order acceptance.
- Support reaches most merchants through their commerce platform rather than through their own engineering.
From checkout to discovery
ACP started as the checkout standard behind Instant Checkout. In March 2026 OpenAI said the first version of Instant Checkout wasn’t flexible enough for merchants and began letting them use their own checkouts. ACP was extended to product feeds and promotions, so today it mostly decides how ChatGPT reads your catalog. The checkout and payment specs below are still published, and in-chat checkout remains for a small set of partners.
Two specs, one handshake
ACP is published as two parts that fit together.
The first covers the commerce flow: how an agent reads a product, opens a checkout session, updates it with an address and a shipping choice, and completes the order against your systems. You keep control of pricing, tax, stock and whether to accept the order at all.
The second covers delegated payment. Instead of handing a card number to an agent, the shopper’s payment credential becomes a token scoped to that one purchase, which you charge through your existing payments stack.
The split is the interesting bit. A merchant can accept agent-placed orders without an agent ever touching payment credentials, and a payments provider can support the token half without knowing anything about your catalog. The specification lives at agenticcommerce.dev.
An open spec beats the marketplace deal it replaces
Picture the alternative. Every assistant builds its own merchant integration, and you negotiate, build and maintain one connection per platform. That is the marketplace pattern, and you already know how it ends: the platform sets the terms because the integration cost lands on you.
An open specification changes that shape. One implementation, done once by your commerce platform, can serve several agents. Switching cost falls, and a little bargaining power moves back toward the merchant.
None of which is settled. ACP is published by two companies with an obvious interest in it becoming the standard, and a published spec is not the same thing as a widely adopted one.
A short evaluation you can finish this week
You are almost certainly not implementing ACP yourself. Your platform is. Knowing what you are signing up for is still your job.
- Read the checkout flow in the spec once. An hour with the documentation tells you which fields an agent will see and which of yours are blank.
- Get your commerce platform’s position in writing. Supported, planned, or not on the roadmap. Ask before a board meeting asks you.
- Ask your payments provider about delegated payment tokens. If they cannot charge one, the rest is academic.
- Map the spec’s required fields onto your catalog. Every place the spec expects a value and your data has a gap is the actual work.
- Write down the terms you would refuse. Fee ceiling, eligible categories, whether you insist on a customer email. Decide that now, not during an integration call.
One spec, or one deal per platform
| Marketplace integration | ACP | |
|---|---|---|
| Who you build for | One platform at a time | Any agent implementing the spec |
| Who sets the rules | The platform | A published spec, revised in the open |
| Seller of record | Often the marketplace | You |
| Customer data | Usually withheld | Whatever the flow passes you |
| Switching cost | High, and paid again each time | Lower, shared across agents |
Further reading: GEO tip of the week: the Agentic Commerce Protocol.
How this term is used
ACP launched as the checkout standard behind Instant Checkout and has since shifted mainly to product discovery. It’s one of about nine competing standards. See agentic commerce protocols for how they compare.
Agentic commerce is early, and its terms and standards are still forming. It’s the commerce branch of AI search marketing, built on organic GEO / AEO visibility.
Frequently asked questions
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Is ACP the same thing as Instant Checkout?
No. ACP is the specification. Instant Checkout is OpenAI’s product built on it, running inside ChatGPT, announced in the same Buy it in ChatGPT post. A shopper experiences Instant Checkout. A merchant’s systems speak ACP. Since March 2026 ACP is used mainly for product discovery, while most purchases finish on the merchant’s own checkout.
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Do I have to implement ACP myself?
Almost certainly not. Support comes through your commerce platform and your payments provider, in the same way card schemes and tax engines reach you. Direct implementation makes sense for large merchants running their own stack, and for nobody else.
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Has ACP become the standard?
Not yet, and calling it one would be premature. It is the most fully published specification in agentic commerce and it has a live implementation behind it, which is more than most proposals manage. Several competing efforts exist, compared in agentic commerce protocols. Standards fights take years and sometimes end in two standards.
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What does supporting it cost?
The specification itself is free to read and implement. The costs sit elsewhere: platform fees on completed orders, engineering time if you build direct, and the catalog clean-up that agentic checkout exposes. That last one is the item most merchants underestimate, and it is worth doing whether or not ACP wins.