Google unveils open UCP standard for AI-driven shopping

Google has released the Universal Commerce Protocol, an open-source standard for what it calls "agentic commerce", and said it has built a first reference implementation for buying flows inside AI Mode in Search and the Gemini app.

Google said UCP sets out a common language for consumer surfaces, merchants and payment providers. The company described the work as a protocol that fits with existing retail infrastructure and aligns with the Agent Payments Protocol, also known as AP2.

Google developed UCP with a group of retailers and commerce platforms. It named Shopify, Etsy, Wayfair, Target and Walmart as collaborators. Google also said more than 20 partners across the ecosystem have endorsed the approach, including Adyen, American Express, Best Buy, Flipkart, Macy's, Mastercard, Stripe, The Home Depot, Visa and Zalando.

Standard approach

Google framed UCP as an attempt to address a pattern of fragmented integrations across commerce services. The company said businesses often build distinct connections for each consumer surface, which creates what it described as an "N x N integration bottleneck".

UCP sets out a standard that covers multiple stages of a buying journey. Google said the scope runs from product discovery and consideration through purchase and order management. The company described a single abstraction layer that sits between consumer surfaces and merchant back ends.

Google said UCP includes a unified integration model, a shared schema for discovery and transport, and an architecture that allows extensions. It also said the protocol takes a security-first approach through tokenised payments and verifiable credentials.

Integration options

Google said businesses can integrate with UCP through APIs, Agent2Agent, and the Model Context Protocol. It said the protocol includes an "embedded option" for merchants that want to keep a customised checkout experience while adopting the standard.

UCP uses the concept of services and "capabilities" as core building blocks. Google listed checkout and product discovery as examples. It said businesses expose the capabilities they want to support, and capabilities can have extensions, such as discounts.

Google also described a discovery mechanism that allows agents to find merchant capabilities and payment options through profiles. It said merchants publish a standard JSON manifest located at /.well-known/ucp. Google said this avoids hard-coded integrations and lets agents discover endpoints and configurations dynamically.

Payments model

Google said UCP uses a modular payments design that separates payment instruments from payment handlers. It described instruments as what consumers use to pay and handlers as the payment processors. Google said this design supports interoperability with existing payment providers and a range of payment methods.

It also said the protocol supports "provable" payments. Google said every authorisation is backed by cryptographic proof of user consent.

Developer tooling

Google published sample code and a software development kit. It described a walkthrough with a demo flower shop that runs on a Python server and a SQLite product database. In the walkthrough, an agent discovers a merchant's capabilities, runs a checkout flow and applies discounts through a checkout request.

Google said UCP also supports identity linking and order management, and that it plans to expand the specification for broader agent-driven commerce experiences.

Google implementation

Google said it has built the first reference implementation of UCP. It said this implementation underpins a buying experience that allows consumers to purchase directly from eligible businesses inside Google's conversational experiences, including AI Mode in Search and Gemini.

Google also said its implementation works with existing payments and wallet providers. It said consumers can use Google Pay, and it said Google Wallet can supply payment and shipping information that a user already stores with the service.

For merchants, Google said participation in its implementation requires an active Merchant Centre account and products eligible for checkout. It said this provides the product information Google needs to surface inventory for purchase within conversational experiences.

Google said it expects the protocol to remain community-driven and said it wants developers, businesses and platform architects to contribute through open-source processes.