What is ACP?

ACP, the Agentic Commerce Protocol, is an open standard introduced by OpenAI together with Stripe. It lets AI assistants complete purchases inside a conversation — the agent discovers products, builds a cart, and checks out on the user’s behalf using a securely delegated payment, while the merchant keeps the customer relationship.

ACP was announced by OpenAI and Stripe. It launched alongside Instant Checkout in ChatGPT, and the specification is published as an open protocol so other platforms and merchants can adopt it.

ACP defines a checkout flow between the AI platform and the merchant: a product feed, a cart/checkout session, and a delegated payment token (powered by Stripe’s Shared Payment Token in the reference implementation) so the merchant charges the customer without the agent ever handling raw card details.

ACP (OpenAI + Stripe) is focused on conversational checkout — completing a purchase inside an assistant like ChatGPT. AP2 (Google) is a broader authorization framework using signed mandates across the A2A agent ecosystem and many payment rails. Both target agentic commerce but from different starting points.

x402 is an HTTP-native protocol for instant per-request stablecoin payments, ideal for agents paying for APIs and data. ACP is a checkout protocol for buying physical and digital goods through an assistant, settling via traditional card rails through Stripe. Different jobs; they can coexist in an agent’s toolkit.

Yes — the protocol is open and the reference flow uses Stripe. Merchants expose a product feed and a checkout endpoint that speaks ACP, then opt into surfaces like ChatGPT Instant Checkout. See the curated resources above for tooling.