Node.js Single Sign-On (SSO) System

This project demonstrates a simple Single Sign-On (SSO) system built with Node.js. It consists of a central SSO Provider and two Client Applications that rely on the provider for user authentication.

Core Components

• SSO Provider (server.ts)

  • Port: 5000
  • Central authority for authentication
  • Manages user credentials and issues JWTs
  • Supports local and Google OAuth login

• Client App 1 (client1.ts)

  • Port: 3001
  • Uses the SSO provider for login and session handling

• Client App 2 (client2.ts)

  • Port: 3002
  • Another app relying on the same SSO provider

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SSO Authentication Flow

Login to Client App 1

1. User opens http://localhost:3001/login.
2. Client App 1 detects no local session and redirects to the SSO Provider.
   • Adds app_id, redirect_uri, and state in the query.
3. SSO Provider presents login options (form-based or Google OAuth).
4. Upon successful login, SSO Provider:
   • Creates a central session
   • Stores it in memory (ssoSessions)
   • Sets a cookie sso_session scoped to localhost:5000
5. SSO Provider issues a JWT (signed using app1-secret) and redirects to:
6. Client App 1 validates token via /sso/validate, creates its local session, and redirects to /dashboard.

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Seamless Login to Client App 2

1. User opens http://localhost:3002/login.
2. Client App 2 redirects to the SSO Provider with similar params.
3. SSO Provider detects the existing sso_session cookie.
4. Skips login, immediately issues a JWT (signed using app2-secret), and redirects to:http://localhost:3002/auth/callback?token=
5. Client App 2 validates token, creates a local session, and logs user in without showing any login page.

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Key Features

• Centralized login using SSO Provider
• Stateless JWT-based token sharing between apps
• Session cookies scoped to provider domain (localhost:5000)
• Seamless login across trusted applications
• Supports both local and Google OAuth login flows

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🚀 Running the Project

1. Start the SSO Provider:

node server.ts

2. Start the client files

ts-node src/client<Number>.ts