fcron - Fcron is a scheduler designed for Unix/Linux systems, especially usefull when your system is not up all the day long.
Charles Proxy - HTTP proxy / HTTP monitor / Reverse Proxy
incron - This program is an "inotify cron" system. It consists of a daemon and a table manipulator.
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.
Anacron - Anacron is a periodic command scheduler. It executes commands at intervals specified in days.
Weer - A HTTP protocol debugger with Chrome DevTools frontend interface