| Category | Tool | Comment |
|---|
| Accessibility | Navigate the site with the keyboard only. Is it possible? Do you get a clear focus indication? | |
| Accessibility | Zoom in and magnify your pages by 200% or even 500%. Is the site still working and do you get (probably) a mobile friendly layout? | |
| HTML | Switch off CSS | A good check for semantic HTML is to switch off CSS in the browser. The document should be usable and readable even without CSS attached. |
| Accessibility | Firefox Accessibility Inspector | Check the entire web page for visual contrast, navigation via keyboard, missing text labels, and visualize tabbing order. It also has a simulator that lets you see what a web page would look like to users with various forms of color vision deficiency, as well as contrast sensitivity loss. |
| Accessibility | IBM Equal Access Accessibility Checker | There is even a node package of the checker available. |
| Accessibility | WebAIM WAVE | Check accessibility patterns |
| Accessibility | WebAIM Contrast Checker | Check contrast of two colors |
| Accessibility | Colorslurp | Check contrast of two colors. Desktop tool for Mac. |
| Accessibility | Color Contrast Accessibility Validator | Check contrast of an entire web page |
| Performance | Lighthouse PageSpeed Insights | Check web page performance. A Lighhouse analysis can also be started through the Chrome Developer Tools, where it is available as a dedicated top-level menu entry. This allows to analyse a website running locally on the developer machine. |
| HTML | W3C Markup Validation Service | Check HTML standard compliance |