Agentic Commerce Protocol (ACP)

The Agentic Commerce Protocol (ACP) is an open standard developed by OpenAI and Stripe that lets AI agents and merchants exchange product feeds, checkout details and delegated payments in a common format. OpenAI announced it on September 29, 2025 alongside Instant Checkout in ChatGPT, and released the specification as open source.

ACP standardizes three things: how a merchant shares its catalog, how an agent starts and completes a checkout, and how payment credentials are passed securely without exposing the buyer's card. The merchant stays the seller of record, while the agent handles discovery and the transaction on the shopper's behalf, which is the core mechanic of agentic commerce.

OpenAI scaled back Instant Checkout in March 2026 and moved checkout into retailer apps, but the protocol with Stripe remains part of its shopping approach. It sits alongside Google's Universal Commerce Protocol as one of the competing standards for agent-led shopping. For brands, the practical point is the same under either: clean, current product data and strong visibility in shopping prompts.