Leading Runtime Application Self-Protection (RASP) tools available today include Contrast Security Protect, Imperva RASP, Hdiv Security RASP, Signal Sciences (Fastly App & API Protection), Sqreen (now part of Datadog), Waratek Secure, and Micro Focus Fortify Runtime, all designed to monitor applications from inside the runtime environment and stop attacks as they occur. These solutions differ in their ability to provide real-time attack detection and automatic blocking, as well as their depth of visibility into application behavior, code execution, and data flows. Many platforms support multiple programming languages and frameworks and integrate with DevSecOps pipelines, CI/CD tools, and application monitoring systems to embed runtime protection within the development lifecycle. Differences also appear in performance impact on production systems, governance and compliance capabilities, scalability for cloud-native or microservices architectures, and ease of deployment and ongoing management. Overall, the effectiveness of these RASP platforms depends on how well they combine runtime monitoring, low-latency protection, and automated threat mitigation to defend applications against attacks such as SQL injection, cross-site scripting (XSS), and other emerging or zero-day threats while maintaining application performance.