Basic authentication with username/password is obsolete. Implement OAuth 2.1 with PKCE (Proof Key for Code Exchange) for public clients. Use JSON Web Tokens (JWT) with short expiration times and refresh token rotation. Always validate tokens on every request.

 

Authentication verifies who you are; authorization determines what you can do. Implement Role-Based Access Control (RBAC) or Attribute-Based Access Control (ABAC). Never trust client-side permissions—always enforce access rules server-side.

 

Validate every piece of incoming data. Use strict type checking, whitelist acceptable values, and sanitize strings to prevent injection attacks. JSON Schema validation libraries can automate this for complex payloads.

 

Rate Limiting: Prevent Abuse I

mplement rate limiting to prevent brute force and DDoS attacks. Use sliding window or token bucket algorithms. Return 429 status codes with Retry-After headers. Consider tiered limits—stricter for unauthenticated requests.

 

Never transmit data over HTTP. Use TLS 1.3 for all API communications. Implement HTTP Strict Transport Security (HSTS) headers. Validate certificates and pin them in mobile applications.

 

Configure Cross-Origin Resource Sharing carefully. Don't use wildcard (*) origins in production. Specify exact allowed domains, methods, and headers. Validate the Origin header server-side.

 

Never break existing clients. Use URL versioning (/v1/, /v2/) or header-based versioning. Maintain old versions for at least 6 months while deprecating them clearly in documentation.

 

Log all API requests with timestamps, IP addresses, and user agents. Use tools like ELK Stack or Datadog to detect anomalies. Set up alerts for unusual traffic patterns or repeated authentication failures.

 

Don't expose internal stack traces or database schemas in error responses. Return generic error messages to clients while logging detailed information internally. Use standardized error formats like RFC 7807 (Problem Details).

 

Implement security headers including X-Content-Type-Options: nosniff, X-Frame-Options: DENY, and Content-Security-Policy. These prevent common attacks like MIME sniffing and clickjacking.

 

Conduct penetration testing quarterly. Use tools like OWASP ZAP or Burp Suite to scan for vulnerabilities. Keep dependencies updated—many breaches exploit known vulnerabilities in outdated libraries.

 

API security is not a one-time setup but a continuous process. By implementing these measures, you protect your data, your users, and your reputation.