UCP (Universal Commerce Protocol)

If every store exposes its own API, an agent that shops on your behalf has to learn hundreds of them. UCP is an attempt at one interface instead: a merchant declares what it supports — product catalog, cart operations, checkout, loyalty, returns, plus any store-specific capabilities — and any UCP-speaking agent can discover those capabilities and transact without a bespoke integration per retailer.

The design leans on negotiation rather than a fixed schema. Both sides state what they can do; the concrete handler for a given step can vary by cart contents, buyer location, or order value, so a large retailer with complex tax and fulfillment logic and a small shop can both be "UCP merchants" without being forced into the same rigid flow. This is capability-discovery applied to commerce.

UCP is developed in the open with Google and Shopify as lead contributors and a broad set of large retailers and card networks backing it, first shown publicly in early 2026 and expanded through the year with additional cart, catalog, and identity-linking capabilities. Many merchants are expected to inherit UCP support through their commerce platform rather than implementing it directly. As of 2026 it is one of several converging agentic-commerce efforts, not a settled winner — and it is commonly paired with ap2-agent-payments-protocol, which handles the payment authorization UCP itself does not.

How it works

A merchant publishes a UCP description of its capabilities. An agent fetches that description, matches it against the user's goal, and calls the relevant operations: search the catalog, add items to a cart, request a checkout quote (which resolves shipping, tax, and discounts), and confirm the order. For steps the merchant handles specially, the description points the agent at the right handler rather than assuming one universal implementation. Post-purchase actions — order status, cancellation, returns — are part of the same interface. Payment is typically delegated: UCP produces the cart and the order, and a payment layer such as AP2 authorizes the charge.

Example

An agent is asked to "find a rain jacket under $120 that ships by Friday." It queries the UCP catalog capability at three retailers, filters by price and a checkout quote that includes delivery estimate, adds the best match to that merchant's cart, requests a final checkout quote (tax and shipping resolved), and hands the resulting order to a payment mandate for the user's approval. The user never visited any of the three sites.

How it differs

Common misconceptions

FAQ