Overview

This guide provides detailed instructions for developers integrating with the Universal Commerce Protocol (UCP) on Google. It covers the necessary steps to enable transactions directly on Google's AI surfaces (Search, Gemini).

Note: The UCP is an evolving standard, and not all features defined in the spec are available on Google's surfaces. Refer to the detailed guides within this site for the most up-to-date information on feature support.

Implementation at a glance

Follow these steps to go live on Google AI surfaces. You can choose to integrate a checkout path (to support purchases directly on Google) or a cart path (to receive shopping carts and hand off to your website).

1. Prepare your Merchant Center account. Configure shipping, returns, and your product feed.
   • Once you're ready, join the waitlist to get in contact with Google for UCP implementation. Your integration must be approved by Google before you can go live on AI Mode in Google Search and Gemini.
2. Prepare your UCP profile. This allows Google to negotiate services and capabilities and discover your payment handlers and public keys for signature verification.
3. Authentication. Secure your API endpoints.
4. Choose your core implementation path:
   • Native checkout path: implement the Native checkout overview to handle full purchases directly on Google AI surfaces. This path also requires you to:
     • Google Pay payment handler to allow users to submit payments.
     • Order lifecycle (post-purchase) to push order updates.
   • Cart path: implement the Cart API to transfer a user's shopping cart from Google surfaces to your website.
5. (Optional) Add extended capabilities:
   • Identity Linking - OAuth 2.0: implement OAuth 2.0 to sync user profiles (replaces the default guest checkout).
   • Promo codes and discounts overview: allow users to apply promotions during checkout.