Creating client IDs

If you wish to require authentication to access your API backend, you must obtain the required client IDs and supply them to the backend using the proper API annotation attribute.

Android

To create the OAuth 2.0 Android client ID, you'll need to have a certificate key fingerprint. If you use Android Studio, a debug keystore and a debug key are created automatically. You can use the debug key for testing purposes, but you must use a release key for production.

Note that the default debug keystore password is android, and the key alias is androiddebugkey. The default location for Linux and macOS is ~/.android.

  1. Generate a debug (or release) key for your Android application, if you don't already have one. If you use Android Studio, it automatically generates a debug key in the debug keystore the first time you build an Android project.
  2. In a Linux or macOS terminal window, you can get the fingerprint of the key using the keytool (included with the Java SDK) as follows:
    keytool -exportcert -alias androiddebugkey -keystore path-to-debug-or-production-keystore -list -v
    The fingerprint looks something like this: DA:39:A3:EE:5E:6B:4B:0D:32:55:BF:EF:95:60:18:90:AF:D8:07:09
  3. Copy and save the key fingerprint that is displayed after your run the above keytool command. You'll need to supply the fingerprint to generate the Android client ID in the GCP Console.
  4. Go to the Credentials page in the GCP Console.
    Go to the Credentials page
  5. From the projects list, select the project containing your API.
  6. If this is your first time creating a client ID in this project, fill out the required fields on the OAuth consent screen.
  7. Select Android as the application type.
  8. In Name, enter a name for your client ID.
  9. In Signing-certificate fingerprint, enter the fingerprint you obtained previously.
  10. In Package name, enter the Android application package name, as specified in your AndroidManifest.xml file.
  11. Click Create.

    You use the generated client ID in your API backend and in your client application.

web client

  1. Go to the Credentials page in the GCP Console.
    Go to the Credentials page
  2. From the projects list, select the project containing your API.
  3. If this is your first time creating a client ID in this project, fill out the required fields on the OAuth consent screen.
  4. Select Web application as the application type.
  5. In Name, enter a name for your client ID.
  6. In Authorized JavaScript origins, enter one of the following:
    • http://localhost:8080 if you are testing the backend locally.
    • https://your_project_id.appspot.com, replacing your_project_id with your actual App Engine project ID if you are deploying your backend API to production App Engine.

  7. Click Create.

    You use the generated client ID in your API backend and in your client application.

What's next

For information about how to support authentication in your Android or JavaScript app, see the following:

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