A free toolkit for manually testing web applications, providing capabilities for intercepting, inspecting, modifying, and replaying HTTP requests and responses during security testing.

A globally accessible knowledge base mapping real-world adversary behavior into tactics, techniques, and procedures used to understand and analyze cyber threats.

Hands-on security games that teach Linux, networking, cryptography, web security, and other cybersecurity concepts through progressively challenging levels.

A nonprofit security organization providing freely available resources on web and application security, including security standards, testing methodologies, vulnerability guidance, and developer-focused projects.

A free, hands-on learning platform for web application security featuring structured lessons and interactive labs covering vulnerabilities such as SQL injection, XSS, authentication flaws, and access control issues.

Browser-based cybersecurity rooms combining guided lessons with practical challenges covering topics such as networking, Linux, web security, and penetration testing.