WordPress.com is now open source, which is incredibly cool.

The new WordPress.com codebase, codenamed “Calypso,” moves WordPress.com away from MySQL and PHP. It’s built entirely in JavaScript, and communicates with WordPress.com only using our REST API. This means the new WordPress.com is a browser-based client for our API, just like any other application built on top of it — lighter, faster, and more flexible for a mobile-focused world.

This is just the beginning, folks. The WordPress REST API will power the web, be it in a browser or in apps, mark my words.