Caffeine is a livecoding environment for the web. After adding it to a webpage, you can use it to change that page live, without reloading, and to store your changes. You can interact with Caffeine through a full graphical interface inside your page, and with your favorite text editor.
We've introduced TypeScript and CSS in the last release and are doing a batch of fixes for them in this release. We're also adding support for new languages: GraphQL queries, embedding CSS-in-JS and JSON are now available in prettier!