# Agentic Commerce Protocols Open standards that let an AI agent discover, check out and pay at a merchant it does not own. | Protocol | Owners | Scope | Status (Oct 2026) | |---|---|---|---| | UCP (Universal Commerce Protocol) | Google + Shopify; Etsy, Wayfair, Target, Walmart | Discovery to returns | Live for eligible US merchants in Search AI Mode and Gemini; Universal Cart since I/O 2026 | | ACP (Agentic Commerce Protocol) | OpenAI + Stripe; Meta on steering group | Checkout only | Spec in beta; Instant Checkout status contested | | AP2 (Agent Payments Protocol) | Google | User consent | Signed "intent" and "cart" mandates as verifiable credentials | | Visa TAP (Trusted Agent Protocol) | Visa | Agent identity | Signed headers on Web Bot Auth; splits browse from pay requests | | Mastercard Agent Pay | Mastercard | Agent identity in the transaction | Tokenised agent IDs; issuer scores risk per agent | ## UCP - Announced at NRF, 11 January 2026. Over 20 endorsers, including Visa, Mastercard, Stripe and Adyen.^[https://developers.googleblog.com/under-the-hood-universal-commerce-protocol-ucp/] - Merchants declare their capabilities. Agents discover them and negotiate what they can handle.^[https://shopify.engineering/ucp] - Works with A2A, AP2 and MCP. ## ACP - Launched September 2025 with ChatGPT Instant Checkout. Apache 2.0.^[https://stripe.com/newsroom/news/stripe-openai-instant-checkout] - Four endpoints: create, update, complete, cancel a checkout session. Payment uses a single-use Stripe token. - One report says Instant Checkout was retired in March 2026 after few Shopify merchants shipped. Another calls it a timing change. Unresolved. ## What it means for AEO - The merchant stays seller of record. The agent owns the customer moment. - Product feeds become the new landing page. Clean price, stock, shipping and return data decide whether an agent can buy. - Agent identity (TAP, Agent Pay, Web Bot Auth) lets merchants trust good bots and block bad ones. - Google holds the stronger position. It owns discovery and checkout in one flow. ---- tags: #boat #ai links: [[Agent Engine Optimisation MOC]] [[Conversational Commerce]] [[Agent-Ready Web Stack]]