🔐 Authentication Implementation with Better Auth

[halilibrahimcelik]

🔐 Authentication Implementation Checklist

Branch: feat/authentication
Project: Finance Tracker
Focus: Better Auth + Google + GitHub + Email/Password

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🎯 Branch Scope & Goals

✅ What This Branch Will Accomplish:

• Complete authentication system setup
• User registration and login functionality
• OAuth integration (Google + GitHub)
• Route protection for future features
• Updated navbar with auth state management

❌ What This Branch Will NOT Include:

• Dashboard implementation (separate branch)
• Transaction management (separate branch)
• Database models beyond auth (separate branch)
• Advanced features like 2FA (future branch)

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📦 Phase 1: Dependencies & Setup

🔧 Install Required Packages

• Install Better Auth core:

  pnpm add better-auth @better-auth/nextjs

• Install OAuth providers:

  pnpm add @auth/google-provider @auth/github-provider

• Install database adapter:

  pnpm add @better-auth/prisma-adapter prisma @prisma/client

🌍 Environment Configuration

• Add auth environment variables to .env.local
• Add .env.local to .gitignore
• Create .env.example for other developers

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🗄️ Phase 2: Database Schema (Auth Only)

📋 Auth-Related Tables Only

• Create User model/table
• Create Session model/table
• Create Account model/table (OAuth)
• Run migrations for auth tables
• Test database connection

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⚙️ Phase 3: Better Auth Configuration

🔧 Core Auth Setup

• Create src/lib/auth.ts configuration file
• Configure email/password provider
• Configure Google OAuth provider
• Configure GitHub OAuth provider
• Set up session management
• Configure auth callbacks

🛠️ API Routes Setup

• Create src/app/api/auth/[...better-auth]/route.ts
• Test API endpoints locally
• Verify auth routes work correctly

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🎨 Phase 4: Authentication UI Components

📁 Component Structure Setup

• Create src/components/auth/ directory
• Create base auth components

🔑 Sign In Page (/signin)

• Create src/app/signin/page.tsx
• Email/password login form with validation
• Google OAuth button
• GitHub OAuth button
• Loading states for all auth methods
• Error handling and display
• Redirect to dashboard on success
• Link to signup page

📝 Sign Up Page (/signup)

• Create src/app/signup/page.tsx
• Email/password registration form
• Form validation
• Google OAuth button
• GitHub OAuth button
• Loading states for all auth methods
• Error handling and display
• Redirect to dashboard on success
• Link to signin page

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🛡️ Phase 5: Route Protection & Middleware

🚧 Authentication Middleware

• Create src/middleware.ts for route protection
• Protect future dashboard routes (/dashboard/*)
• Protect future API routes (/api/protected/*)
• Redirect unauthenticated users to /signin

🔒 Auth Context/Hooks

• Create src/lib/auth-client.ts for client-side auth
• Create src/hooks/useAuth.ts custom hook

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🧭 Phase 6: Navbar Integration

🎨 Update Navbar Component

• Add conditional rendering based on auth state
• Show user profile when authenticated
• Add logout functionality
• Update navbar styling for auth states

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🔵 Phase 7: OAuth Provider Setup

🔍 Google OAuth Configuration

• Create Google Cloud Console project
• Enable Google Sign-In API
• Configure OAuth consent screen
• Add authorized redirect URIs
• Get client ID and secret
• Test Google login flow

⚫ GitHub OAuth Configuration

• Create GitHub OAuth App in settings
• Configure application details
• Add authorization callback URL
• Get client ID and secret
• Test GitHub login flow

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🧪 Phase 8: Testing & Validation

✅ Manual Testing Checklist

• Email/password registration works
• Email/password login works
• Google OAuth registration works
• Google OAuth login works
• GitHub OAuth registration works
• GitHub OAuth login works
• Logout works correctly
• Protected routes redirect to signin
• Session persists across browser refresh
• Navbar updates correctly on auth state change

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✅ Success Criteria

🎯 This Branch is Complete When:

• ✅ Users can register with all 3 methods (email, Google, GitHub)
• ✅ Users can login with all 3 methods
• ✅ Protected routes work (redirect to signin)
• ✅ Navbar shows correct state (authenticated vs not)
• ✅ Sessions persist across browser refresh
• ✅ Logout works and clears session
• ✅ All error cases handled gracefully
• ✅ OAuth flows work in both development and production

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📊 Branch Metrics

📅 Start Date: October 5, 2025
🎯 Target Completion: 2 weeks
⏱️ Estimated Time: 1-2 weeks
🏷️ Priority: High
👤 Assignee: @halilibrahimcelik

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🆘 Resources

• Better Auth Documentation
• Google OAuth Setup
• GitHub OAuth Setup