Matrix Metadata Problem: the server sees everything except your messages
People pick Matrix because of end-to-end encryption. But E2EE only protects message content — everything around it is plaintext.
The server sees:
- Your ID, IP, client type and version, device you use
- Your presence, typing status, read receipts
- Which rooms you join and when you join/leave
- Who else is in those rooms → your entire social graph
- Room names, topics, avatars (all plaintext state)
- For every message: who sent it, which room, a millisecond timestamp, type, size
And federation copies all of that to every other server whose users are in the room. Your “social footprint” isn’t one copy — it’s as many as there are servers.
Yes, it’s good that there is a solution to the problem