SSL Server Test : This free online service performs a deep analysis of the configuration of any SSL web server on the public Internet.
mitmproxy : mitmproxy is your swiss-army knife for debugging, testing, privacy measurements, and penetration testing. It can be used to intercept, inspect, modify...
webhint : webhint is a linting tool that will help you with your site's accessibility, speed, security and more, by checking your code for best practices and co...
XSS Filter Evasion Cheat Sheet - OWASP : This article is focused on providing application security testing professionals with a guide to assist in Cross Site Scripting testing.
Intern : Intern is a complete test system for JavaScript designed to help you write and run consistent, high-quality test cases for your JavaScript libraries a...
Memorable site for testing clients against bad SSL configs.