Wattspeed

Excelent for a quick one-click verification of HTML, accessibility, responsivenes and performance. Available for firefox and crome. Very appreciated.

useful and easy to use. the only thing missing is an export option :D

Very Useful

amazing

Great tools and very helpful!

Very usefull. If we can choose the country it'll be perfect

Extremely helpful way to get a quick look at a website. I am often too busy or lazy to use the much more in depth Website Auditor feature in Advanced Web Ranking; this makes a decent little substitute and saves visiting websites for the information. All SEOs should have this.

Amazing thing: it combines information sources like BuildWith, PageSpeed Insights, Google's Mobile Test, W3C HTML5 validator and social metrics from G+, LinkedIn, Pinterest and Facebook. Beside of this the tool informs about main organic keywords and top competitors. Pretty handy and free!