RuneScape: DragonwildsGuideEvery Dragonwilds world is one file, <world name>.sav, in %LOCALAPPDATA%\RSDragonwilds\Saved\SaveGames on Windows. Difficulty, PvP, and the Standard,…
Every Dragonwilds world is one file, <world name>.sav, in %LOCALAPPDATA%\RSDragonwilds\Saved\SaveGames on Windows. Difficulty, PvP, and the Standard, Custom, or Creative rule set are stored inside it, so to run a custom world you create it in your own game, then upload that .sav with Upload World on your server's Backups card (or Upload Existing World while creating the server). Do not rename the file: the server loads the save by its name, and your World Name setting is set to match on import.
The Dragonwilds dedicated server has no difficulty, PvP, or game mode settings of its own. It loads whatever world it is given and plays by that world's rules. That is why the dashboard shows you a World Name and a Server Password but no difficulty slider: the way to pick your rules is to pick the world. A fresh server starts a new Standard world under the name on your card.
Start RuneScape: Dragonwilds on your PC and create a new world.
Choose the rule set (Standard, Custom, or Creative), the difficulty, and whether PvP is on. Give the world the name you want your server to carry; it is what friends will search for, and it must be 3 to 16 characters of letters, numbers, spaces, hyphens, and underscores.
Load into it once so the game writes the save, then leave the world and close the game so the file is not being written while you copy it.
Press Win+R, paste %LOCALAPPDATA%\RSDragonwilds\Saved\SaveGames, and press Enter. You will see one .sav per world, each named after its world. Pick the one you just made. Next to it there may be a backup copy of the same world, named <world>.sav.backup, <world>.backup or <world> backup.sav depending on the game version. Upload it along with the .sav or leave it out; either works. Your characters are not in this file; they live in the separate SaveCharacters folder and stay on your PC, so nothing about your character travels with the upload, and nothing is lost either.
Other platforms:
Steam Deck: the same folder sits inside Steam's Proton prefix, at ~/.local/share/Steam/steamapps/compatdata/1374490/pfx/drive_c/users/steamuser/AppData/Local/RSDragonwilds/Saved/SaveGames.
Xbox app / PC Game Pass: saves are kept in a packed format the game manages itself, not as a .sav you can copy, so a world made there cannot be uploaded.
PlayStation, Xbox and Switch 2: consoles do not give access to save files, so console-made worlds cannot be uploaded. Create the world on the server instead, and pick its rules in the game.
Mac: Dragonwilds does not run natively on Mac. Cloud gaming (GeForce NOW or Xbox Cloud Gaming) keeps saves in the cloud service, so there is no local file to upload.
Open My Servers and stop your Dragonwilds server if it is running.
On the Backups card, choose Upload World and drop the .sav in (a zip containing it works too). Upload one world at a time.
Wait for the import to finish. A backup of the server's current world is taken first, so the world that was there is one click away if you ever want it back.
Look at your server settings: World Name now matches the file you uploaded. Leave it that way.
Start the server. Friends search the new world name in the game's Public Worlds browser or use the invite code on your card.

Setting up a brand new server? Switch on Upload Existing World while creating it and the same steps apply.
The server loads SaveGames/<World Name>.sav, nothing more clever than that. Three things follow:
Never rename the file before uploading. A renamed file is a different world as far as the server is concerned.
Changing World Name later starts a new, empty world. The old file stays on the server untouched. Change the name back and the old world loads again exactly where you left it.
You can keep several worlds on the server and switch between them by changing the name, one at a time. Only the world whose name matches is live.
Editing the config file to set difficulty or PvP. Those values are not in DedicatedServer.ini; they are in the save.
Uploading a folder of several worlds at once. Upload one world per import. A folder that holds one world plus its backup copy is fine; two different worlds are refused.
Uploading a character file. Characters are separate from worlds and stay with each player.
Expecting more than 6 players. The cap is the game's, whatever world you upload.
Ask in Discord or email support@haptic.gg with the name of the .sav you uploaded and what the server card says now. We can check which world the server actually loaded.