How to create Oauth2 credentials for Google Apps

In this guide, I’ll share the process for customising the authentication configuration for Google Apps (Gmail) using the new Authentication Platform dashboard in GCP. The procedures remain the same for other apps, such as Google Sheets, Calendar, Drive, etc. So let’s begin.

Setting up Google OAuth

In this section, we’ll go through the process of setting up a Google Developers account/Project and creating an OAuth 2.0 Client ID using the new dashboard.

Note: If you already have a Google Cloud project set up, you can skip the first step.

Step 1: Create a Google Cloud Project (Optional)

If you don’t already have one, create a Google Cloud Project

This gives you a workspace where you can configure OAuth clients and APIs

Step 2: Open the OAuth Consent Screen

1. In the Google Cloud Console, navigate to APIs & Services → API Library → Search for Gmail API and enable it → OAuth consent screen.

   

2. This opens the new Auth Platform dashboard.

If this is your first time in the project, the screen will look like this:

Step 3: Configure the Consent Screen

Click Get Started and follow the onboarding wizard:

1. App Information

   • App Name

   • User support email (dropdown)

2. Audience

   • Select Internal (only your org’s accounts) or External (any Google user)

     

3. Contact Information

   • Add developer contact details

4. Acknowledgement

   • Review and click Create

     

Once done, you’ll see the Consent Screen Overview page.

Step 4: Create OAuth Client Credentials

1. On the Consent Screen Overview, click "Create OAuth Client."

   

2. You’ll be redirected to the Clients page.

3. Configure the client:

   • Application type: e.g., Web application

   • Client name: choose any name for your app

   • Authorized JavaScript origins: (you can use https://platform.composio.dev, if you’re trying it out on the dashboard).

     <https://your-frontend.com>

   • Authorized redirect URIs:

     <https://backend.composio.dev/api/v1/auth-apps/add>

   • Click Create

     

4. After creation, Google will generate your OAuth Client ID and Client Secret. • You can copy them immediately, or later find them again on the Clients page by clicking the client entry.

   

Step 5: Set App Status (Publish or Test)

• Testing Mode:

  • Keep your app in testing while building.

  • Add specific test users (emails) to validate authentication.

• Production Mode:

  • Once you set the app status as In production, it becomes available to all Google users.

  • Depending on your configuration, you may need to submit the app for Google verification.

  

For now, add yourself (or your test users) under the Test Users section to validate your setup.

Creating the Auth Config in Composio

With your OAuth credentials ready, navigate to the Composio Dashboard to configure Google authentication.

1. Click Create Auth Config

2. Choose Gmail from the toolkit list.

   

3. Make sure OAuth2 is selected

4. Check “Use your own developer credentials”

Step 6: Fill in the Auth Config

Go to Manage Auth Config and paste your credentials:

• Client ID → from GCP OAuth Client

• Client Secret → from GCP OAuth Client

• Redirect URI → must match the one you configured in GCP

  <https://backend.composio.dev/api/v3/toolkits/auth/callback>

You can also customize the scopes if needed (default scopes are usually sufficient).

Finally, click Create Auth Config. You’ll now have a Config ID (ac_...) that can be used in your app code to trigger authentication via Google

Extending to Other Google Services

The process above was for setting up Google OAuth with Composio Auth Platform. You can follow the same steps to integrate other Google services (Sheets, Calendar, Drive, etc.) into your Composio setup.

• Simply go to APIs & Services → Library in your GCP project.

• Enable the APIs you want (e.g., Google Sheets API, Google Calendar API).

• Reuse the same OAuth Client you created earlier or create a new one if needed.