Useful Websites for Webmasters

There are several websites where you can get free or low-cost suggestions to improve website performance. Here are some of the tools I use most:

Why No Padlock? is a useful resource when you cannot figure out why, despite setting up your SSL certificate and configuring your website to use HTTPS, you can not get that green lock to show up!

Screenfly from Quirk Tools lets you compare how your website will look on different devices. It is a good idea to check a few pages on this site any time you do a major redesign, to make sure your site is responsive and looks good on different devices.

I want to find a replacement for this though because it seems to recognize that I am logged in. I am worried that it is not correctly rendering.

PageSpeed Insights gives you suggestions from Google that can help improve your website performance, which can in turn help with your search engine ranking.

Note: Not all of the PageSpeed suggestions make sense. For example, my score is brought down by using widely-supported image formats ( .jpg and .png ) and by using Google Analytics to monitor website traffic. Carefully consider the potential side effects before implementing any suggested changes.

Other websites that will grade your pages and suggest ways to improve performance – I use Pingdom about as often as I do PageSpeed Insights. – Every now and then I will check GT Metrix

W3 Schools

Even with 20 years of coding experience, sometimes I need a little refresher or I simply run across something I never needed to do before. is an excellent resource to learn or brush up on your HTML, CSS, Javascript, PHP, ASP, SQL, and more. 

Can I use? is a simple website to see which browsers support specific tags. For example, It shows that the <picture> tag is still unsupported in Internet Explorer.

Colorblind Simulators

I am currently looking for a good colorblindness simulator. At one point I planned to write my own, but I am happy to see that several already exist. 

So far the ones I have tried are either hard to use or, in the case of the “Colorblinding” chrome extension, use way to much CPU. (even when the extension is not in use. – My CPU usage dropped significantly after removing the Colorblinding chrome extension.)