Manages customer loyalty program memberships for merchants.

This service allows all merchants, including non-advertisers, to share their first-party customer data of loyalty program members. Google uses this data to personalize organic free listing shopping experiences, in compliance with the [Merchant Center Terms of Service](https://support.google.com/merchants/answer/160173).

The service follows a non-standard, imperative pattern, exposing a single `ManageLoyaltyCustomerMatch` method rather than conventional resource identifiers and CRUD operations. This design protects user privacy by preventing the discovery of a customer's presence or membership status through standard GET or LIST methods.

| [ManageLoyaltyCustomerMatch](https://developers.google.com/merchant/api/reference/rpc/google.shopping.merchant.loyaltycustomers.v1/LoyaltyCustomerMatchService/ManageLoyaltyCustomerMatch) |
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| `` rpc ManageLoyaltyCustomerMatch(`https://developers.google.com/merchant/api/reference/rpc/google.shopping.merchant.loyaltycustomers.v1/Types/ManageLoyaltyCustomerMatchRequest`) returns (`https://developers.google.com/merchant/api/reference/rpc/google.shopping.merchant.loyaltycustomers.v1/Types/ManageLoyaltyCustomerMatchResponse`) `` Manages (inserts, updates, or removes) a customer's loyalty tier information. This method serves as a single interface for all changes to a customer's loyalty status. The specific action (insert, update, or remove) is determined by the current state of the merchant-to-customer association and the `loyalty_tier` value provided in the request. For more information on how to use this method, see [Overview of the loyalty customer match service](https://developers.google.com/merchant/api/guides/loyalty/customer-match-service). **Operation Logic:** - **Upsert (Insert/Update):** Providing any valid tier other than `NON_MEMBER` will associate the customer with that tier. If an association already exists, it will be updated; otherwise, a new one will be created. - **Removal:** Setting `loyalty_tier` to `NON_MEMBER` will remove any existing loyalty association for the customer. **Privacy Note:** To protect user privacy, this method consistently returns a `200 OK` status with a default `LoyaltyCustomer` response if the customer's identifier cannot be matched to a Google account or if the user has not opted into loyalty personalization. Authorization scopes :   Requires the following OAuth scope: - `https://www.googleapis.com/auth/content` For more information, see the [OAuth 2.0 Overview](https://developers.google.com/identity/protocols/OAuth2). |