Siege is an http load testing and benchmarking utility. It was designed to let web developers measure their code under duress, to see how it will stand up to load on the internet. Siege supports basic authentication, cookies, HTTP, HTTPS and FTP protocols. It lets its user hit a server with a configurable number of simulated clients. Those clients place the server “under siege.”
boomerang is a piece of javascript that you add to your web pages, where it measures the performance of your website from your end user's point of view. It has the ability to send this data back to your server for further analysis. With boomerang, you find out exactly how fast your users think your site is.
Get an instant report of how your website measures up to the best practices.
Check connection encryption, content security, information disclosure and cookies. Compare your results with today's top sites.
Breaking CSS is easy. Checking every responsive page element is hard. That’s why there's BackstopJS.
mtools is a collection of helper scripts to parse and filter MongoDB log files (mongod, mongos), visualize log files and quickly set up complex MongoDB test environments on a local machine.
Free online service that allows you to test your emails for Spam, Malformed Content and Mail Server Configuration problems
Online test to help speeding up heavy web pages
Diagnostic.css is a stylesheet which allows the user to test for common errors in a page's markup.
Chrome extension for detecting and simulating frontend Single Points Of Failure. Detects likely third-party single points of failure as you browse and allows you to Simulate 3rd party resources being unavailable.
Also, here: https://chrome.google.com/webstore/detail/spof-o-matic/plikhggfbplemddobondkeogomgoodeg
Burp Suite is an integrated platform for performing security testing of web applications. Its various tools work seamlessly together to support the entire testing process, from initial mapping and analysis of an application's attack surface, through to finding and exploiting security vulnerabilities.
toxy is a fully programmatic and hackable HTTP proxy to simulate server failure scenarios and unexpected network conditions, built for node.js/io.js.
The Big List of Naughty Strings is a list of strings which have a high probability of causing issues when used as user-input data.
A modern load testing framework
Define user behaviour with Python code, and swarm your system with millions of simultaneous users.
an accessibility visualization toolkit that aims to reduce the friction of a11y testing
Buildbot is an open-source framework for automating software build, test, and release processes.
jscs is a code style checker. jscs can check cases, which are not implemented in jshint, but it does not duplicate jshint functionality, so you should use jscs and jshint together.
This is JSHint, a tool that helps to detect errors and potential problems in your JavaScript code.
Codeception PHP Testing Framework is designed to work just out of the box. This means its installation requires minimal steps and no external dependencies preinstalled (except PHP, of course). Only one configuration step should be taken and you are ready to test your web application from an eye of actual user.
The tweet-sized continuous integration app for PHP development.
YSlow for PhantomJS