This page provides guidance on planning your API migration and outlines the
required steps.

## Plan your migration

1. **Map your Content API for Shopping methods to Merchant API methods.**

   Understand the new methods and resources required for Merchant API.
2. **Understand the most significant changes that apply to your migration.**

   Review the following resources to help with your migration:
   - **Migrate from Content API overview**: This details the major changes to be aware of in Merchant API
   - **Sub-API specific migration guides** : Review the specific sub-API migration guides you need as they provide critical information such as new field mappings. For an example, see [Migrate products
     management](https://developers.google.com/merchant/api/guides/compatibility/products).
   - [**Merchant API reference**](https://developers.google.com/merchant/api/reference/rest) provides the details of Merchant API resources and methods.
   - The **Quickstart** guide shows how to quickly start using Merchant API to create an account and upload a sample product.
   - **Feature-specific guides**: For new feature implementation or for more clarification, you can review the feature guides provided in the navigation.
3. **Identify the sub-APIs that you plan to migrate and want to implement.**

   Determine two things:
   - The Merchant API features you need to migrate
   - The new features you want to implement

   Once you've done this, you can determine the amount of effort and a priority
   list of sub-APIs to work on.

   If you cannot migrate your entire Content API implementation initially,
   prioritize the following sub-APIs based on importance and complexity.
   - [Accounts](https://developers.google.com/merchant/api/guides/accounts/overview)
   - [Products](https://developers.google.com/merchant/api/guides/products/overview)
   - [Data sources](https://developers.google.com/merchant/api/guides/data-sources/overview)
   - [Reports](https://developers.google.com/merchant/api/guides/reports/overview)

   > [!NOTE]
   > **Note:** You can approach this on a case-by-case basis, depending on your integration type. For example, a feature such as [Inventories](https://developers.google.com/merchant/api/guides/compatibility/inventories) may be a higher priority.

## Migration steps

1. **Register as a developer**
   To use the Merchant API, you must create a link between your
   Google Cloud project and your primary Merchant Center account.
   This one-time registration is required for every Google Cloud
   project you use with Merchant API. You can follow the whole process in the
   [Overview page](https://developers.google.com/merchant/api/guides/quickstart#register_as_a_developer).

   > [!NOTE]
   > **Note:** If you need to transition to a new Google Cloud project or manage multiple projects during migration, see [Manage and transition Google Cloud projects](https://developers.google.com/merchant/api/guides/accounts/manage-transition-gcp-projects).

2. **Test different methods** to help you ramp up. We recommend using [Google
   APIs Explorer](https://developers.google.com/apis-explorer) to perform basic tests.

   The format of request URLs for Merchant API is

       https://merchantapi.googleapis.com/{SUB_API}/{VERSION}/{RESOURCE_NAME}:{METHOD}...

3. **Leverage** our code samples and client libraries.

   To help reduce the implementation time and benefit from
   [gRPC](https://developers.google.com/merchant/api/overview#grpc-rest), use the [client
   libraries](https://developers.google.com/merchant/api/client-libraries) and [code
   samples](https://developers.google.com/merchant/api/samples).

   The guides include code sample snippets. For example, see
   [Add a product](https://developers.google.com/merchant/api/guides/products/add-manage#add_a_product).
4. **Test simple user journeys.**

   Conduct user journey testing on all the sub-APIs and functionality you plan
   to migrate with the following goals:
   - Your migrated resources and calls have correct response results.
   - The error ratio remains low.

## Plan your roll-out

We recommend the following approach:

- Implement one sub-API or method at a time.
- Implement to only a small segment of the business at a time.
- Monitor for issues at all times.

## Implement your migration

1. **Work on coding using the new resources and endpoints.**

   After initial testing and development of a release plan, integrate
   Merchant API into your workflows.
2. **Monitor.**

   Prepare to address potential issues.