Agentic Commerce Protocol

What it is

The Agentic Commerce Protocol is an open standard for AI commerce: a shared set of rules that lets AI agents, people and businesses work together to complete a purchase ^[1]. OpenAI announced it on 29 September 2025, alongside a consumer-facing feature built on top of it called Instant Checkout ^[1]. The two are easy to confuse, so it helps to separate them. Instant Checkout is what a shopper encounters inside ChatGPT; the protocol is what a merchant or a developer implements in order to take part ^[1].

How a purchase works

Instant Checkout lets U.S. ChatGPT Plus, Pro and Free users buy directly from U.S. Etsy sellers inside the chat ^[1]. A shopper describes or asks for something, and the product results ChatGPT shows are organic and unsponsored, ranked purely on relevance to the user ^[1]. If the shopper decides to buy, the merchant handles the order, the payment and the fulfilment using its existing systems, while ChatGPT passes information between the user and the merchant ^[1]. The merchant therefore remains the party that processes and fulfils the sale, and the assistant acts as the channel through which the buyer reaches it ^[1].

That split is the core design decision. Checkout does not move into the chat as a new marketplace run by the model maker; the transaction stays with the seller, and the conversation becomes one more place where it can start ^[1].

Who built it

OpenAI co-developed the protocol with Stripe and leading merchant partners ^[1]. At announcement, more than a million Shopify merchants were named as coming soon, among them Glossier, SKIMS, Spanx and Vuori ^[1]. OpenAI also says more than 700 million people use ChatGPT each week ^[1], which indicates the size of the audience a merchant would be reaching through such a channel.

Why it is open

OpenAI open-sourced the protocol so that more merchants and developers can build integrations ^[1]. An open standard, in the ordinary engineering sense, is a specification anyone can implement rather than a private arrangement between two companies; publishing it means a retailer, a platform or an agent builder can support the same flow without negotiating a separate deal each time ^[1]. The protocol was written to describe how agents, people and businesses cooperate on a purchase, not how one company's checkout button works ^[1].

What the first version covered

At launch, Instant Checkout supported single-item purchases only, with multi-item carts to follow ^[1]. The launch scope was also narrow in other ways: the buyers were U.S. ChatGPT users and the sellers were U.S. Etsy sellers ^[1]. Those limits describe a first version rather than the finished idea, and the protocol was released as something other merchants and developers could extend ^[1].