Set up the API
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Every request your application sends to the Postmaster Tools API must include an authorization token. The token also identifies your application to Google.
About authorization protocols
Your application must use OAuth 2.0 to authorize requests. No other authorization protocols are supported. If your application uses Sign In With Google, some aspects of authorization are handled for you.
Authorizing requests with OAuth 2.0
All requests to the Postmaster Tools API must be authorized by an authenticated user.
The details of the authorization process, or "flow," for OAuth 2.0 vary somewhat depending on what kind of application you're writing. The following general process applies to all application types:
- When you create your application, you register it using the Google API Console. Google then provides information you'll need later, such as a client ID and a
client secret.
- Activate the Postmaster Tools API in the Google API Console. (If the API isn't listed in the API Console, then skip this step.)
- When your application needs access to user data, it asks Google for a particular scope of access.
- Google displays a consent screen to the user, asking them to authorize your application to request some of their data.
- If the user approves, then Google gives your application a short-lived access token.
- Your application requests user data, attaching the access token to the request.
- If Google determines that your request and the token are valid, it returns the requested data.
Some flows include additional steps, such as using refresh tokens to acquire new access tokens. For detailed information about flows for various types of applications, see Google's OAuth 2.0 documentation.
Here's the OAuth 2.0 scope information for the Postmaster Tools API:
| Scope |
Meaning |
https://www.googleapis.com/auth/postmaster.readonly |
Allows read-only access to Postmaster Tools data. |
To request access using OAuth 2.0, your application needs the scope information, as well as
information that Google supplies when you register your application (such as the client ID and the
client secret).
Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 4.0 License, and code samples are licensed under the Apache 2.0 License. For details, see the Google Developers Site Policies. Java is a registered trademark of Oracle and/or its affiliates.
Last updated 2025-08-28 UTC.
[null,null,["Last updated 2025-08-28 UTC."],[],[],null,["# Set up the API\n\nEvery request your application sends to the Postmaster Tools API must include an authorization token. The token also identifies your application to Google.\n\nAbout authorization protocols\n-----------------------------\n\nYour application must use [OAuth 2.0](https://developers.google.com/identity/protocols/OAuth2) to authorize requests. No other authorization protocols are supported. If your application uses [Sign In With Google](https://developers.google.com/identity/gsi/web), some aspects of authorization are handled for you.\n\nAuthorizing requests with OAuth 2.0\n-----------------------------------\n\nAll requests to the Postmaster Tools API must be authorized by an authenticated user.\n\nThe details of the authorization process, or \"flow,\" for OAuth 2.0 vary somewhat depending on what kind of application you're writing. The following general process applies to all application types:\n\n1. When you create your application, you register it using the [Google API Console](https://console.cloud.google.com/). Google then provides information you'll need later, such as a client ID and a client secret.\n2. Activate the Postmaster Tools API in the Google API Console. (If the API isn't listed in the API Console, then skip this step.)\n3. When your application needs access to user data, it asks Google for a particular **scope** of access.\n4. Google displays a **consent screen** to the user, asking them to authorize your application to request some of their data.\n5. If the user approves, then Google gives your application a short-lived **access token**.\n6. Your application requests user data, attaching the access token to the request.\n7. If Google determines that your request and the token are valid, it returns the requested data.\n\nSome flows include additional steps, such as using **refresh tokens** to acquire new access tokens. For detailed information about flows for various types of applications, see Google's [OAuth 2.0 documentation](https://developers.google.com/identity/protocols/OAuth2).\n\nHere's the OAuth 2.0 scope information for the Postmaster Tools API:\n\n| Scope | Meaning |\n|-------------------------------------------------------|---------------------------------------------------|\n| `https://www.googleapis.com/auth/postmaster.readonly` | Allows read-only access to Postmaster Tools data. |\n\nTo request access using OAuth 2.0, your application needs the scope information, as well as\ninformation that Google supplies when you register your application (such as the client ID and the\nclient secret)."]]
