webhint : webhint is a linting tool that will help you with your site's accessibility, speed, security and more, by checking your code for best practices and co...
Diagnostic.css : Diagnostic.css is a stylesheet which allows the user to test for common errors in a page's markup.
Also : https://github.com/karlgroves/diagnostic.css
mobiReady : The mobiReady testing tool evaluates mobile-readiness using industry best practices & standards.
CodeceptJS : CodeceptJS is a new testing framework for end-to-end testing with WebDriver (or others). It abstracts browser interaction to simple steps that are wri...
Which loads faster? : Pages compete head-to-head in your browser to see who's fastest!
Monitor the accessibility of your websites with pa11y-dashboard, and protect against accessibility errors creeping into your codebase.