Recently I wanted to use a Jetpack block for the WordPress Gutenberg editor, specifically the Slideshow Block, which I think is very slim and elegant compared to other Slideshow blocks on the WordPress.org plugin directory.
The one thing I didn’t want to do, though, is to connect my site to WordPress.com. For the most part because I didn’t intend to use any of the functionality that requires the WordPress.com connection.
The difficulty in this: normally, you can’t actually use Jetpack until you connect the site to your WordPress.com account. This behavior is in place so you can enjoy a friction-less experience after the connection is established (i.e. you can activate any of its features whether or not it needs the connection).
In my case, the connection is not needed for using the Slideshow block since it works with the local media library.
So, I present not a hack but an official way to use Jetpack without a WordPress.com connection: it’s called Offline Mode.
You activate it by adding a constant or filter to your wp-config.php, for example:
define( 'JETPACK_DEV_DEBUG', true );
While it is intended for local installs and actually development, it is useful if you just want to use a single feature of Jetpack that doesn’t require the connection.
Many people say that Jetpack is slow because it’s so big. It is indeed huge from a file size and feature perspective, but also it’s very optimized, so that it will only load the PHP or JS code it needs. The other files lay dormant in your file system and don’t contribute to the loading or rendering time of your site.