Proxyman.io - Proxyman is a high-performance macOS app, which enables developers to view HTTP/HTTPS requests from apps and domains.
Medium CLI - A command line Interface for reading Medium stories
httpbin(1) - HTTP request and response service
Mac CLi - OS X command line tools for developers
Endpoints - View and respond to requests on an HTTP endpoint
HTML Product Hunt - Product Hunt disguised as HTML code so you can browse freely