Problem Statement
What security considerations should you implement in Next.js API routes and Route Handlers?
Explanation
Implement authentication and authorization checks at the start of every protected endpoint verifying tokens or sessions before processing requests, validate and sanitize all user inputs to prevent injection attacks using libraries like validator or zod, and use CORS headers properly to restrict which origins can access your APIs. Apply rate limiting to prevent abuse using tools like upstash/ratelimit or custom Redis-based solutions, implement CSRF protection for state-changing operations especially with cookies, and use HTTPS only in production with secure httpOnly cookies for sensitive tokens. Never expose internal errors to clients returning generic messages instead while logging detailed errors server-side, sanitize database queries using parameterized statements or ORMs to prevent SQL injection, and implement proper error handling that doesn't leak sensitive information. Consider using API keys for service-to-service communication, implement request signing for critical endpoints, set appropriate cache headers to prevent sensitive data caching, and regularly audit dependencies for vulnerabilities using npm audit or similar tools.
