... integrators can track breaking changes. Practically, ACP defines three main pieces; a Product Feed for discovery, an Agentic Checkout API for stateful, in-conversation checkout, and a Delegated Payment flow so a merchant’s existing PSP securely handles payment credentials and settlement. Merchants remain the merchant-of-record—orders, fraud controls, payment authorization/capture, refunds, and post-purchase communication all stay on their systems while the agent surfaces status to the buyer.