Every Valheim world keeps its seed in a small .fwl file next to the save. Drop that file below and read the seed back, no hex editor needed. Handy if you took over a dedicated server, lost the note you scribbled the seed on, or typed one in and ended up in a completely different world.
Runs in your browser, nothing leaves your computer
Drop your .fwl file here
or
YourWorld.fwl or YourWorld.fwl.old — the small file next to the world's .db
The file is read locally and never leaves your computer.
A Valheim world is two files that share a name: a large .db with the terrain and everything you've built, and a small .fwl with the metadata, including the seed. On Windows, worlds you play locally sit here:
%userprofile%\AppData\LocalLow\IronGate\Valheim\worlds_local
Worlds synced through Steam Cloud sit in Steam's userdata folder instead (892970 is Valheim's app ID). On Linux, local worlds live under .config:
C:\Program Files (x86)\Steam\userdata\<SteamID>\892970\remote\worlds
~/.config/unity3d/IronGate/Valheim/worlds_local
Dedicated servers keep the same pair in their world folder. On a Host Havoc Valheim server, open the file manager in the control panel and grab the .fwl from the save directory. It's a few hundred bytes, so the download is instant.
Turn a server password into the ServerPasswordHash and ServerPasswordSalt values that SpaceEngineers-Dedicated.cfg expects.
Move your world onto hardware that stays up around the clock: instant setup, automatic backups of your .db and .fwl files, DDoS protection and NVMe storage.