Universal Commerce Protocol
The Universal Commerce Protocol, or UCP, is an open standard for purchases that AI agents make with online merchants. Google launched it on 11 January 2026 and developed it with Shopify, Etsy, Wayfair, Target and Walmart. The protocol covers the whole purchase, from searching the catalog and filling a cart to checkout, order status and support after the sale.
Merchants publish a profile at a fixed address on their website that lists what their shop supports, for example checkout, orders or a loyalty program. An agent reads that profile, compares it with its own and uses only the functions both sides understand. The merchant remains the seller of record and keeps the customer relationship.
How merchants and agents negotiate
The merchant publishes its profile under /.well-known/ucp, and the agent sends the address of its own profile with every request. The merchant calculates which capabilities both sides support and answers with that intersection, as Shopify describes the design.
UCP splits a shop into a core with checkout session, line items and totals, into capabilities such as Checkout, Orders and Catalog, and into extensions such as fulfillment. Each of these parts carries a version number of its own. A company can define an extension under its own internet domain without asking a central registry, so a loyalty provider can publish points for every merchant that uses it.
Payments in UCP
For payment, UCP builds on the Agent Payments Protocol (AP2) with payment mandates and verifiable credentials, and it links customer accounts with OAuth 2.0. The specification, the list of capabilities and the developer guides are published at ucp.dev.
Agents reach the merchant through REST or JSON-RPC, and UCP supports the Model Context Protocol and Agent2Agent. That lets a merchant serve agents that are built on MCP servers with the same profile.
Checkout in AI Mode and Gemini
With the launch, Google announced that UCP would power a checkout on eligible product listings in AI Mode in Search and in the Gemini app. Shoppers pay with Google Pay and the payment methods saved in Google Wallet, and PayPal was announced as the next option. More than 20 companies endorsed the protocol, among them Adyen, American Express, Mastercard, Stripe, Visa and Zalando.
On 15 October 2026 Google launched the Universal Cart in the United States, a cart in Search and Gemini that collects products from several retailers and pays through UCP. Nike, Sephora, Target, Walmart and Wayfair took part from the start, and each retailer remained the seller of record.
UCP and ACP compared
The Agentic Commerce Protocol of OpenAI and Stripe specifies the checkout between agent and merchant and the token for the payment provider. UCP covers a wider range, from catalog search to order management, and leaves the payment proof to AP2. A merchant that sells through ChatGPT and through Google therefore implements both protocols.
Upcoming payments events in Germany
What is UCP?
UCP is the Universal Commerce Protocol, an open standard from Google and Shopify for purchases by AI agents. It defines how agents find products, fill carts, pay and follow orders with any merchant that publishes a UCP profile.
Who developed the Universal Commerce Protocol?
Google developed UCP together with Shopify, Etsy, Wayfair, Target and Walmart. The code and the specification are published as an open project on GitHub, where other companies can propose changes.
Does UCP work outside retail?
The project extends the protocol beyond retail to other industries. A draft specification for lodging is available, and a version for food ordering is announced on ucp.dev.
Is UCP checkout available in Europe?
At launch, checkout through UCP worked with eligible retailers in the United States. The Universal Cart of October 2026 also started only in the United States, and Google named no date for the European Union.
Universal Commerce Protocol and Finance Loop
Finance Loop covers UCP and the other building blocks of agentic payments in its Payments & Digital Money track. Finance Loop is a media partner of Capital & Code in Frankfurt, a conference whose program includes AI and agentic payments.
Finance Loop is a professional network and has the goal of driving the institutional use of emerging technologies in finance, such as AI, digital payments, cloud and blockchain solutions. Finance Loop helps its members build skills and personal networks in these fields: Investment & Digital Assets, Payments & Digital Money, Digital Infrastructure & Sovereignty, and Risk & Compliance.