A Personal Data Server for the AT Protocol
Bluesky runs on a federated protocol called AT Protocol. Your account lives on a PDS, a server that stores your posts, profile, follows, and cryptographic keys. Bluesky hosts one for you at bsky.social, but you can run your own. Self-hosting means you control your data; you're not dependent on any company's servers, and your account + data is actually yours.
This software isn't an afterthought by a company with limited resources. It is a superset of the reference PDS, including:
Full compatibility with Bluesky's reference PDS: same endpoints, same behavior, same client compatibility. Everything works.