Implement Google SSO (OAuth2) – Backend

[Alexandrbig1]

Priority: High
Difficulty: Advanced
Type: Backend Feature

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Description:
Set up Google Single Sign-On (SSO) in the CoreX backend. The goal is to allow users to register/login with their Google account.

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Requirements:

• Install and configure Google OAuth 2.0:
  • Either with passport-google-oauth20 or google-auth-library.
• Create endpoints:
  • GET /auth/google – redirect to Google login.
  • GET /auth/google/callback – handle Google’s response.
• Flow:
  • Verify Google profile (id, email, name).
  • If user exists → return JWT.
  • If new user → create in MongoDB (authProvider: 'google'), then return JWT.
• Securely store required environment variables:
  • GOOGLE_CLIENT_ID
  • GOOGLE_CLIENT_SECRET
  • GOOGLE_CALLBACK_URL
• Document usage in README.

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Acceptance Criteria:

• User can authenticate with Google and receive a JWT.
• New Google users are automatically saved in DB.
• Errors (invalid token, failure to fetch user) are handled.
• API is documented for frontend use.

[its-Pratik-15]

i want to contribute assign me this task

[Alexandrbig1]

@its-Pratik-15, are you sure you'll be able to implement this task? Have you experience with this task?

[its-Pratik-15]

I recently learned about OAuth in college, and I’d love to try implementing it!

[Gautam-Bharadwaj]

@Alexandrbig1 Sir, I would like to request this project. I have the experience and am confident I can complete it successfully.

[dikamjit-borah]

Hi @Alexandrbig1 I would like to work on this feature. I have experience building authentication systems in Node.js/Express backends.