Regex101.com is an interactive regular expression console that lets you debug your expressions in real-time.

Creates easy to read HTML file from axe-core accessibility results object

A tool to calculate the contrast ratio between any two valid CSS colors.

Great tool for checking color contrast for both text and images of text.

Accessibility Insights for Web helps developers quickly find and fix accessibility issues.

Accessibility engine for automated Web UI testing

Simple JMeter performance tests API

Static analysis at ludicrous speed.

A Pastebin alternative