Decoder - Instantly decode error and status codes
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.
HTTP Status Dogs - Hypertext Transfer Protocol Response status codes, and dogs
Embeddable - Build Remarkable Analytics Experiences. The toolkit for building fast, interactive, fully-custom analytics experiences into your app.
HTTP Status Tester - Test URLs in bulk for their HTTP responses, by ex-Google
Proxyman.io - Proxyman is a high-performance macOS app, which enables developers to view HTTP/HTTPS requests from apps and domains.