With the rapid adoption of RESTful APIs in web, mobile, and cloud-based ecosystems, ensuring their security has become a critical challenge. Despite the availability of established standards such as OAuth 2.0, TLS, and JWT, real-world implementations often remain vulnerable due to inadequate input validation, weak authentication practices, and insufficient logging or monitoring mechanisms. This research proposes a middleware-based security framework designed to enhance REST API resilience through layered protection and real-time threat mitigation. The middleware acts as an intermediary security layer that validates incoming requests, enforces authentication and authorization policies, and performs intelligent logging and anomaly detection before allowing data flow to backend services. Key contributions include the design and implementation of a modular middleware architecture, seamless integration with existing authentication systems, and a unified logging and alerting mechanism to support proactive incident response. To evaluate the framework, controlled local experiments were conducted using simulated attack payloads targeting common vulnerabilities such as SQL injection, cross-site scripting, and insecure object references. The results demonstrate a significant reduction in successful attack attempts and minimal performance overhead, indicating that middleware-based security can provide an effective and practical defense for RESTful APIs without compromising efficiency [1][7].

RESTful APIs Middleware Security Threat Mitigation API Authentication Rate Limiting Injection Attacks JWT Web Application Security