Charles Proxy - HTTP proxy / HTTP monitor / Reverse Proxy
glogg - glogg is a multi-platform GUI application to browse and search through long or complex log files.
Weer - A HTTP protocol debugger with Chrome DevTools frontend interface
klogg - klogg is the fork of glogg - the fast, smart log explorer.
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.
SPHW - LogViewer - A free platform-independent tool for monitoring log files in real-time.