WhatWeb : WhatWeb identifies websites. Its goal is to answer the question, “What is that Website?”. WhatWeb recognises web technologies including content manage...
Hoppscotch : A free, online, open source API request builder
WebScarab : WebScarab is a framework for analysing applications that communicate using the HTTP and HTTPS protocols.
Squoosh : Squoosh is an image compression web app that allows you to dive into the advanced options provided by various image compressors.
Phantomas : PhantomJS-based web performance metrics collector and monitoring tool
BackstopJS automates visual regression testing of your responsive web UI by comparing DOM screenshots over time.