WordPress.com, the fully hosted version of WordPress, has a received one of its biggest updates ever today. Codenamed Calypso, Automattic rewrote WordPress.com from scratch — everything is new under the hood. Here are the big changes.

First, WordPress.com is now fully separated from the WordPress core. WordPress.com is now an admin interface that interacts with the WordPress core just like any other third-party interface and app out there. It uses a REST API to fetch your posts, publish new ones, upload photos and more.

Second, the team behind WordPress.com switched to an entirely new stack. Instead of using PHP and MySQL, the developers built everything using JavaScript and API calls. It means that when you go to the website, the server will distribute a fully working WordPress client that mostly runs in your browser.

It’s a Single Page Application, meaning that you will get very few loading screens when you interact with the interface. It should work well on your phone and tablet as well — everything is responsive. If you were using the WordPress admin backend, you can still go directly to your backend. But you also have another option now on WordPress.com if you are using a hosted WordPress.com blog, a self-hosted WordPress with the Jetpack plugin or a WordPress VIP site (like TechCrunch).

Finally, everything is open source and on GitHub. You can look at the code, fork it and reuse it as long as you comply with the GNU General Public License version 2.

But the team didn’t stop there. You can also download a new Mac app to access WordPress.com. In many ways, this app works like the Slack desktop app. It leverages web technologies and desktop features so that you get more or less the exact same thing as on the WordPress.com website, but with a few goodies, such as notifications. Windows and Linux apps are in the works.

I downloaded the app and played with it for a few minutes. If you’re familiar with the WordPress.com interface, you’ll feel right at home as it looks exactly the same. But it’s always nice to have an app icon in the Dock.

So why did Automattic, the company behind WordPress.com, go through this painful rewriting process? WordPress.com now feels and works like a modern web app. It’s back in the game against newcomers, such as Medium.

While the editor lacks many features that WordPress power users make use of (including TechCrunch writers), WordPress.com is a clean, efficient writing interface that should appeal to many people who are writing today on Medium.

25 percent of the web today runs on WordPress. This is no small feat, and WordPress isn’t the young, hustling startup working against bigger companies — it’s a web giant. With today’s move, Automattic proves that it is still aware of its environment and potential threats. It’s an encouraging sign for the future of WordPress.

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