Yahoo! YSlow!

GTmetrix is a free tool that analyzes your page's speed performance. Using Page Speed and YSlow, GTmetrix generates scores for your pages and offers actionable recommendations on how to fix them.

PageSpeed is addon for Firebug (debugger addon for Mozilla Firefox ) for analyzing of page loading process and suggesting to webmaster how speed up page loading. Javascript obfuscating, image resizing, CSS merging and vise versa.

Run a free website speed test from multiple locations around the globe using real browsers (Firefox, IE, Chrome, Android and iOS) and at real consumer connection speeds. You can run simple tests or perform advanced testing including multi-step transactions, video capture, content blocking and much more. Your results will provide rich diagnostic information including resource loading waterfall charts, Page Speed optimization checks and suggestions for improvements.

Without any installation, we continuously analyze your web pages to detect quality and loading times issues. At any time, you can see the evolution of the major performance indicators of your pages on your dashboard, or in your weekly emailed reports.

Yellow Lab Tools checks a website for both it's performance and the quality of the HTML, CSS and JavaScript code.

Lighthouse is an open-source, automated tool for improving the quality of web pages. You can run it against any web page, public or requiring authentication.

Site Toolbox for the website owner, web engineer, SEO analyst, web developer, webmaster and everyone.

Website speed test, DNS lookup service incl EDNS client subnet, fast geolocation for IP or hostname, HTTP response headers, FREAK attack tester and more.

StatusCake Tools allows you to check the speed and load time of your website. Simply enter the website URL and check one of the locations from around the world you want the website checked from.

MachMetrics continually monitors the speed of your website. So you know exactly how your pages are performing throughout the day, around the world, and on various devices

neXpert is an add-on to Fiddler Web Debugger which aids in performance testing web applications. neXpert was created to reduce the time it takes to look for performance issues with Fiddler and to create a deliverable that can be used to educate development teams.

Get free notifications if your page speed changes, fast and easy.