Here you’ll find a list of tools I’ve developed over the years, to make working with various CSS3 features a bit easier. Since they’re for developers, most of them only work in recent browsers. Also, obviously if you use a tool to help you with a CSS3 feature, it probably won’t work in browsers that don’t support that feature.
The CSS3 Test
Exactly how much CSS3 does your browser support?
Dabblet
An interactive CSS playground. Pretty much my most successful project so far, with thousands of visitors every day.
Animatable
A CSS transitions gallery that shows what’s possible with even the most basic of transitions: one property, two values.
cubic-bezier.com
A tool that helps you work with the easing functions of CSS3 transitions & animations and share them with others.
CSS.coloratum
A tool that helps you convert between the different CSS-accepted color formats (including name keywords) as well as share them with others.
CSS3 patterns gallery
An interactive gallery that demonstrates what’s possible with just CSS gradients. It also allows you to edit the code, to experiment with gradients yourself.
CSS gradients please!
A tool that converts the standard gradient syntax to -webkit-gradient and adds the rest of the prefixes
CSS3 structural pseudo-class selector tester
A tool that helps you learn how the :nth-whatever() CSS3 pseudo-classes work.
CSS3 learning tool
A tool that shows CSS3 newbies some of the things that CSS3 can do, as a reply to a challenge posted in Ajaxian.