1. Create a Google Cloud Project

1. Go to the Google Cloud Console.
2. Click Create New Project.
3. Name it something like unified-calendar.

2. Enable Required APIs

1. Inside your project, go to APIs & Services → Library.
2. Search for Google Calendar API.
3. Click Enable.

3. Configure OAuth Consent Screen

This step is mandatory.

1. Go to APIs & Services → OAuth Consent Screen.
2. Select External and click Create.
3. Fill in:
   • App name
   • User support email
4. Click Save and Continue.
5. Add Test Users: Only added email addresses will be able to connect calendars.
6. If you want to add new users later, make sure to add their email here as well.

4. Create OAuth Client

1. You will be redirected to the overview page.
2. Go to the Clients tab.
3. Click Create Client.
4. Select Web Application.
5. Add the following Authorized Redirect URI:
   http://localhost:3000/api/oauth2callback
6. Click Create and copy your Client ID and Client Secret, or download the JSON file for later use.

You are done with the setup.

5. Connect in the Calendar Application

1. Return to the Calendar Application.
2. Click "Got it, let's go!".
3. A popup will appear.
4. Enter your Client ID and Client Secret.
5. Click Save.

Your application is ready!

Important

When connecting your Google account, make sure to grant all calendar permissions. If you do not select the required permissions, the application will not be able to view or create calendar events.