API Authentication
Implement secure authentication mechanisms for APIs using modern standards and best practices.
Authentication Methods
| Method | Use Case | Security Level |
|---|---|---|
| JWT | Stateless auth, SPAs | High |
| OAuth 2.0 | Third-party integration | High |
| API Keys | Service-to-service | Medium |
| Session | Traditional web apps | High |
JWT Implementation (Node.js)
javascriptconst jwt = require('jsonwebtoken'); const generateTokens = (user) => ({ accessToken: jwt.sign( { userId: user.id, role: user.role }, process.env.JWT_SECRET, { expiresIn: '15m' } ), refreshToken: jwt.sign( { userId: user.id, type: 'refresh' }, process.env.REFRESH_SECRET, { expiresIn: '7d' } ) }); const authMiddleware = (req, res, next) => { const authHeader = req.headers.authorization; // Validate authorization header format if (!authHeader || !authHeader.startsWith('Bearer ')) { return res.status(401).json({ error: 'Malformed authorization header' }); } const parts = authHeader.split(' '); if (parts.length !== 2) { return res.status(401).json({ error: 'Malformed authorization header' }); } const token = parts[1]; if (!token) { return res.status(401).json({ error: 'No token provided' }); } try { req.user = jwt.verify(token, process.env.JWT_SECRET); next(); } catch (err) { res.status(401).json({ error: 'Invalid token' }); } };
Security Requirements
- Always use HTTPS
- Store tokens in HttpOnly cookies (not localStorage)
- Hash passwords with bcrypt (cost factor 12+)
- Implement rate limiting on auth endpoints
- Rotate secrets regularly
- Never transmit tokens in URLs
Security Headers
javascriptapp.use((req, res, next) => { res.setHeader('X-Content-Type-Options', 'nosniff'); res.setHeader('X-Frame-Options', 'DENY'); res.setHeader('Strict-Transport-Security', 'max-age=31536000'); next(); });
Additional Implementations
See references/python-flask.md for:
- Flask JWT with role-based access control decorators
- OAuth 2.0 Google integration with Authlib
- API key authentication with secure hashing
Common Mistakes to Avoid
- Storing plain-text passwords
- Using weak JWT secrets
- Ignoring token expiration
- Disabling HTTPS in production
- Logging sensitive tokens
