When comparing Codepen vs Glitch, the Slant community recommends Codepen for most people. In the question“What are the best web development playgrounds?” Codepen is ranked 3rd while Glitch is ranked 6th. The most important reason people chose Codepen is:
CodePen makes it really easy to export code as a zip or Github Gist.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Easily export your pen
CodePen makes it really easy to export code as a zip or Github Gist.

Pro Real time output
Pro Lots of support for frameworks and preprocessors
CodePen has an impressive amount of support for preprocessors (such as Jade, Haml, Slim, Sass, Less, Stylus, Coffeescript and PostCSS). There is also plenty of frameworks and libraries to pick from (Foundation, Bootstrap, Angular, D3, Backbone, Ember etc.).
Pro Great display/profile page
The codepen profile page allows you to display all of your public pens, and control which order you want them to be viewed in. This is great for showing off your work to possible employers, other devs etc..
Pro Easily fork pens
To fork a pen only requires clicking one button, and you'll be able to modify the pen on your own account.

Pro Great community pens
You can search through other pens, either by keyword or popular, picked or recent.
Pro Embed support
You can embed Glitch apps anywhere on the web. Embed works easily with most blogging tools like Medium and Wordpress.
Pro Git support
Each project has its own git repo hosted by Glitch. And you can export/import to Github.
Pro Easily fork projects with remix
Click "remix" to create a new copy of a project and edit instantly
Pro Run any node.js or simple web project easily from the browser
Pro Great community pens
Lots of excellent featured projects, click to "remix" to edit them yourself.
Pro Get help easily
The friendly "raise your hand" feature allows you to get help with your code from the community.
Cons
Con No private pens with free account
There is an option on Codepen for private pens, however it requires upgrading to a Pro account ($9/month).
