mcron - mcron is GNU's implementation of cron. It is a 100% compatible replacement for Vixie cron.
Fiddler - Fiddler is a debugging program for websites.
Anacron - Anacron is a periodic command scheduler. It executes commands at intervals specified in days.
Proxyman.io - Proxyman is a high-performance macOS app, which enables developers to view HTTP/HTTPS requests from apps and domains.
fcron - Fcron is a scheduler designed for Unix/Linux systems, especially usefull when your system is not up all the day long.
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.