Free tool
Check your world before you move it to a dedicated server. Point it at your Valheim, Palworld or Terraria save and it tells you whether the files a server actually needs are there, and what to fix before you upload them.
Your files stay in your browser. They are never uploaded, and no account is needed. The only thing we receive is an anonymous counter: which game you checked, the result category, and the issue codes. No file names, world names, seeds or contents.
Drop your world files here
The folder named after your world. Valheim 1.0 saves each world as a folder of _main and .chunk files. A world last saved before 1.0 is a <world>.fwl and <world>.db pair instead. With Steam Cloud on, and always on macOS, the live world is in your Steam folder under userdata/<id>/892970/remote/worlds. Otherwise look in %USERPROFILE%\AppData\LocalLow\IronGate\Valheim\worlds_local on Windows. A folder there with only cacheMinimap files is the map cache, not the world.
This browser cannot select a whole folder. Open the world folder and select every file inside it, or for an older world select the .fwl and .db pair.
Three checks before upload
Almost none of the failed migrations we see are corrupted saves. They are complete worlds uploaded with a piece missing, or a world that quietly brought settings from the machine it used to live on. Both are visible before anything is uploaded.
Valheim needs both .fwl and .db. Palworld needs Level.sav plus Players. A modded Terraria world needs its .twld. Miss one and the server can look healthy while loading an empty world, fresh characters or a world stripped of its mods.
Palworld's WorldOption.sav can override the destination's identity and port. The server runs, but it can disappear from the community browser.
A newer build can change its save format, and an older server refuses it: tModLoader trails vanilla Terraria and cannot open worlds from the newest release. The checker names the version, and reports a format it does not know as unrecognized, never corrupt.
Private by design
The checker reads small slices locally and forgets them when you close the tab. It never uploads a .chunk, .db or Level.sav, so a 400 MB world is as quick to check as a new one.
Ready for a destination?
GHosting gives the world file access, a live console and simple settings, so the move is an upload and a restart rather than a Linux project. Pay once for a fixed term, or subscribe if you would rather it renew.
No. The check runs in your browser: the files are read in small slices on your own machine and the report is built there. What we do receive is the same anonymous counter every page on this site sends, plus which game you checked, the result category and the issue codes, so we can tell whether the tool is useful. It never carries a file name, world name, seed, player id or any file content, and you can confirm all of that in your browser network tab.
It means you have the files a migration needs and none of the known traps apply, so the move is worth attempting. It is not a promise the world is undamaged or that the destination server will load it. Keep your source copy until the server has run once and you have joined.
Valheim 1.0 no longer writes them. Each world is now a folder named after it, holding _main files that describe the save and .chunk files for each region of the map. Move the whole folder. Valheim only loads the newest save in it whose four _main files are all present, and a server stops loading the world if any region file the save lists is missing. A world last saved before 1.0 is still a .fwl and .db pair, and a 1.0 server converts it to a folder the first time it saves.
With Steam Cloud saving on, worlds_local only keeps the drawn map for each world, in a folder with the world's name. The world itself is in your Steam folder under userdata, then your account id, then 892970/remote/worlds. That is the folder to check and upload.
A world hosted from the Palworld client carries WorldOption.sav, and Palworld reads that in preference to PalWorldSettings.ini. It is a complete settings store, so it also brings the old server name and advertised port, which is why a healthy server can be missing from the community browser while direct connections work.
The world does. The co-op host character does not, because a client-hosted world stores the host under a fixed identity while a dedicated server keys every player to their own account. Everyone else keeps their character. The host needs a separate migration.
tModLoader is built on an older Terraria release than the one on Steam, and it refuses any world saved by a newer release. A world that was opened in the latest vanilla Terraria can only run on a vanilla server until tModLoader catches up. The checker reads the world version and tells you which kind of server can run it.
It is where tModLoader keeps everything that comes from mods: modded blocks, items in chests, NPCs and boss progress. Upload the .wld without it and the world loads with all of that missing. Always move the pair together, with the same name.
Valheim, Palworld and Terraria. Those are the games where a migration fails for reasons you can see in the files before uploading.
