REST API Security
REST API security refers to the set of practices, controls, and design principles used to protect RESTful web services from unauthorized access, data breaches, injection attacks, and other threats.
REST (Representational State Transfer) APIs are the backbone of modern web and mobile applications, making their security critical. REST API security encompasses multiple layers of defense, starting with transport security via TLS/HTTPS to encrypt data in transit, and extending through authentication, authorization, input validation, and output encoding.
Core security principles for REST APIs include using standard authentication mechanisms such as OAuth 2.0 or API keys with proper rotation policies, implementing role-based or attribute-based access control for every endpoint, validating and sanitizing all input parameters to prevent injection attacks, returning minimal error information to avoid leaking implementation details, and using appropriate HTTP status codes and methods to maintain semantic correctness.
Additional hardening measures include enforcing content-type validation to reject unexpected media types, implementing CORS policies to control cross-origin access, using security headers such as Content-Security-Policy and X-Content-Type-Options, versioning APIs to manage deprecation securely, and monitoring API traffic for anomalous patterns. Rate limiting should be applied to all endpoints, with stricter limits on authentication endpoints. Sensitive data should never appear in URLs or query strings, as these are often logged by proxies and web servers. Regular penetration testing and automated security scanning of REST APIs help identify vulnerabilities before attackers exploit them.