Implement UCP: the merchant guide.

Who this guide is for

Merchants, e-commerce platforms and digital teams that want their offer to be buyable by AI agents through the Google and Shopify UCP standard. It separates what is configuration (Merchant Center path) from what is engineering (protocol path), and what remains data groundwork either way.

Path 1: Google's reference implementation

Google built the first reference implementation of UCP: it powers native checkout in AI Mode (Search) and the Gemini app, with Google Pay. To take part: Established

1. Have an active Merchant Center account. This is the entry point: Google relies on declared product data to surface inventory in its conversational experiences.
2. Provide checkout-eligible products, compliant with the Merchant Center feed specification (accurate price, availability, attributes).
3. Follow Google's integration guide (developers.google.com/merchant/ucp) and complete the merchant interest form.
4. Complete the checkout integration following the guide's dedicated instructions.

Availability: rollout starts in the United States, with announced expansions to Canada and Australia, then the United Kingdom. Established

Path 2: integrate the protocol directly

UCP is an open, vendor-agnostic standard: a merchant or platform can expose its own capabilities, independently of Google. The core of the integration: Established

1. Publish the discovery manifest at /.well-known/ucp: a JSON document declaring the protocol version, services (e.g. dev.ucp.shopping), capabilities and payment handlers.
2. Expose your chosen capabilities: checkout (the transactional core), with extensions such as discount or fulfillment, plus identity linking and order management.
3. Wire payment handlers: the protocol separates instruments (what the buyer uses) from handlers (who processes), with handlers such as Google Pay or Shop Pay. Every authorization is backed by cryptographic proof of consent.
4. Pick your transport: REST APIs, MCP or A2A depending on your stack, the standard supports all three.
5. Start from the official tooling: the Python SDK (python-sdk) and the samples repository (samples) on the protocol's GitHub, including a complete demo server.

What UCP does not do for you

The protocol transports your offer, it does not improve it. Three workstreams remain entirely on the merchant side, whichever path you choose: Established

• Catalog quality: rich attributes, accurate prices and stock, clean identifiers. Agents compare at machine speed; poor data is eliminated data.
• Policy clarity: shipping, returns, warranties, eligibility. What is ambiguous for a human is blocking for an agent.
• Governance: what you allow, refuse and audit when an agent acts on behalf of a customer.

These map to the layers of this hub's four-layer framework, and the readiness audit methodology scores them before you commit engineering time.

Frequently asked questions