Federacy - Bug bounty and security testing platform.
Charles Proxy - HTTP proxy / HTTP monitor / Reverse Proxy
IssueHunt - IssueHunt is a crowd funding service for opensource contributors and owners!
HTTP Toolkit - Beautiful, cross-platform & open-source tools to debug, test & build with HTTP(S). One-click setup for browsers, servers, Android, CLI tools, scripts and more.
HackerOne - HackerOne provides a platform designed to streamline vulnerability coordination and bug bounty program by enlisting hackers.
Weer - A HTTP protocol debugger with Chrome DevTools frontend interface