Universal Commerce Protocol

Before UCP, an AI shopping agent that wanted to buy something from Merchant A and then Merchant B needed a custom API integration with each one. UCP solves this by defining a common protocol: merchants publish a UCP manifest (a machine-readable document declaring their capabilities, payment handlers, and authentication requirements), and any compliant agent can discover and transact with them using the same protocol calls.

Launched in January 2026 as a collaboration led by Google alongside Shopify, Walmart, Target, Etsy, Wayfair, and payment providers including Visa, Mastercard, and Stripe, UCP handles the full commerce lifecycle: product discovery, cart management, checkout, payment negotiation, and returns. For secure payments by autonomous agents, it integrates with AP2 (Agent Payments Protocol), which adds cryptographic proof that the buyer authorized the transaction within defined spending limits.

For builders, UCP is the equivalent of what HTTP is to the web: it is the shared communication layer that makes the agentic commerce ecosystem interoperable rather than a collection of proprietary integrations. If you are building a consumer AI agent that needs to transact across merchants, or if you are building ecommerce infrastructure that wants to be selectable by AI agents, UCP is the spec to implement. It powers checkout in Google's AI Mode and the Gemini app, and as of mid-2026 is actively deployed across major US retailers.