HTTP mocking and expectations library
Keep multiple browsers & devices in sync when building websites. http://browsersync.io
BDD / TDD assertion framework for node.js and the browser that can be paired with any testing framework.
Navigation scripting & testing utility for PhantomJS and SlimerJS
Start apps from your browser and get local domains without editing /etc/hosts http://i.imgur.com/DrLjbIi.gif
Monkey testing library for web apps and Node.js
Yeoman - a set of tools for automating development workflow
Modern Prototyping Tool
Holder renders image placeholders entirely on the client side.
Visual/CSS regression testing with PhantomJS
Browser compilation library – a build tool for applications that run in the browser
CSS coding style formatter