Checkout Integration

To enable users to check out, you must implement the Native checkout integration. This involves creating a standard REST API that allows Google to programmatically manage the checkout flow with your servers. This method provides the most seamless experience for users. Initially, Google will render the user interface for the buyer, with future plans to support more agentic experiences.

For detailed instructions, see the Native integration guide.

Authentication

While no authentication is required, Google supports the following options for use when calling the business's checkout API endpoint.

API Keys

HTTP Header: X-API-Key

A shared secret value which will be used in Google's UCP API client request HTTP header to authenticate with the checkout endpoint.

HTTP Header: Authorization: Bearer <Access Token>

Following RFC 6749, Google's UCP Platform agent uses the following properties to request the access tokens needed for checkout endpoint interaction.

Property Description
Client Id A unique string representing the client (e.g. Google's UCP API client)
Client Secret A password type string used to authenticate with the authorization server
Authorization endpoint URL The URL to the OAuth2 API endpoint
Format Basic authentication HTTP header or HTTP body
Encoding Form data or JSON