name: auth-skill description: Implement secure authentication systems including signup, signin, password hashing, JWT tokens, and Better Auth integration.

Authentication System Skill

Instructions

1. User Signup

   • Collect email and password
   • Validate input fields
   • Hash password before saving
   • Store user in database

2. User Signin

   • Verify email exists
   • Compare hashed passwords
   • Handle invalid credentials
   • Return auth response

3. Password Hashing

   • Use bcrypt or argon2
   • Never store plain text passwords
   • Apply proper salt rounds

4. JWT Tokens

   • Generate access token on signin
   • Include user ID in payload
   • Set token expiration
   • Verify token on protected routes

5. Better Auth Integration

   • Configure Better Auth provider
   • Connect with database
   • Use built-in session handling
   • Secure cookies and tokens

Best Practices

• Always hash passwords
• Use HTTPS only
• Set short token expiry
• Store secrets in environment variables
• Protect all private routes

Example Flow

// Signup
User → Hash Password → Save User

// Signin
User → Verify Password → Generate JWT

// Protected Route
Request → Verify JWT → Allow Access