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
Uptime Kuma : Uptime Kuma is an easy-to-use self-hosted monitoring tool.
The Coach : The coach helps you find performance problems on your web page. Think of the coach as a modern version of YSlow. The coach will give advice of how you...
Mink : Mink is an open source acceptance test framework for web applications, written in PHP 5.3.
Monitor the accessibility of your websites with pa11y-dashboard, and protect against accessibility errors creeping into your codebase.