What is a PDS on Bluesky?
Updated
In short: a PDS (Personal Data Server) is the server where your Bluesky account lives. It keeps your posts, likes, follows and images, handles your login, and hands your data to the apps you use. Most people are on Bluesky's own servers, but an account can live on another provider's PDS or a self-hosted one, and it can move without losing its followers.
How Bluesky fits together
Bluesky is built on the AT Protocol, an open system where the pieces are separate, so no single company has to run them all (more in What is the Atmosphere?):
- Your identity (DID): a permanent ID such as did:plc:…. It never changes, even when your handle or server does.
- Your handle: the readable name, like name.bsky.social or your own domain, that points to your DID.
- Your PDS: the server that stores your account's data and signs you in.
- The network: services collect updates from every PDS and build what you see: timelines, threads, like and follower counts.
- The apps: the Bluesky app and many others read from the same network, so one account works everywhere.
Which PDS is an account on?
The bskycheck profile tool shows an account's PDS, its identity history (handle changes and server moves) and the AT Protocol apps it has used. Free, no login.
Why use another PDS?
- Where your data lives: some providers host accounts in a particular region, for example in Europe.
- Community: some communities run their own server for their members.
- Independence: your account doesn't depend on one company's servers.
- Control: technical users can run their own PDS with the open-source software Bluesky publishes.
Whichever PDS you use, you still see and talk to everyone on Bluesky. Choose a provider you trust: it holds your account and your login.
One account, many apps
Because your data lives in your PDS and not inside one app, the same account works in other AT Protocol apps: blogs like WhiteWind and Leaflet, Tangled for code, Smoke Signal for events, teal.fm for music and more. The profile tool shows which of these apps an account has used, its "Atmosphere footprint".
Moving to another PDS
An account can move to another PDS and keep its DID, handle, followers and posts, because everything points to the DID, not to the server. Moving is still a fairly technical step today; some providers offer tools to help. The profile tool's identity history shows past moves, such as to Eurosky or a self-hosted server.
Questions
What does PDS stand for?
Personal Data Server: the server that stores a Bluesky account's data and handles its login.
Is my Bluesky data stored on Bluesky's servers?
If you signed up in the Bluesky app with the default settings, yes: your account is on one of Bluesky's own PDS servers. Accounts can also live on other providers' servers or self-hosted ones.
Can I move my Bluesky account to another server?
Yes. Your DID stays the same, so you keep your handle, followers and posts. It is still a fairly technical process today.
What is the difference between a PDS and an app?
The PDS stores your account; the app is what you use to read and post. The same account works in the Bluesky app and in other AT Protocol apps.
What is the AT Protocol?
The open protocol Bluesky is built on. It separates your identity, your data and the apps, so accounts can move between servers and many apps can share the same network.
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bskycheck is an independent project, not affiliated with Bluesky. Spotted something out of date? Tell @bskycheck.com.