CodePen is my favorite and Top of my list. CodePen is having some cool and unique feature which makes it one of the Most Popular Online Code Editor among Web Developers.
Feature of CodePen are
- You can use preprocessor syntaxes like Sass, LESS, Stylus. Markdown, Haml, Slim, Jade
- Showcase talent using CodePen Portfolio and design your own portfolio page.
- You can Use the Hire Me feature to find freelance work.
- Any Pen can be embedded on any other website.
Dabblet is an interactive code editor for quickly testing snippets of CSS and HTML code. It uses -prefix-free, so that you won’t have to add any prefixes in your CSS code. It allows you to save your work in Github gists, embed it in other websites and share it with others.
Thimble, by Mozilla makes it very easy to create and share your own web pages. You can write and edit HTML and CSS in your browser on one side of your page, with Live Preview on the other side. You can then share you page with your friends in one click.
CSSDesk is another code editor which is having very simple interface and easy to use. It purely focuses on CSS and HTML and is one of the oldest online code editor. You can use it for basic CSS and HTML design.