Fiddler - Fiddler is a debugging program for websites.
Airtable - Airtable works like a spreadsheet but gives you the power of a database to organize anything. Sign up for free.
Proxyman.io - Proxyman is a high-performance macOS app, which enables developers to view HTTP/HTTPS requests from apps and domains.
StatusGator - Monitor all your hosted applications, vendors, and websites, and keep your team informed of outages. StatusGator is the world's premier status aggregator, status page, and website monitoring tool.
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.
WrapAPI - Build an API on top of any website