ModHeader

Chrome extension to modify headers

Classic Cache Killer

Chche Management

Conftest

A utility to help you write tests against structured configuration data

Selenium WebDriver

Browser driver API

Lighthouse

Scanning tool that audits SEO, performance and other web best practices

Advanced RestClient Extension

API Testing Add-on

Postman

API Testing Tool

Pa11y

Range of free and open source tools to help designers and developers make their web pages more accessible.

Contrast Checker

Checks contrast for WCAG compliance