Worlds: switch, upload and reset

The Worlds tab

The Worlds tab lists every world on your server, its size, and which one is active right now.

The active world is the one your server opens on start, and its name lives in server.properties under level-name. Switching worlds writes the new name there, and the world only opens after you restart the server.

Switch world

Pick the world in the table and press Activate. Restart a running server to open the new world. The old world stays exactly where it is, and you can go back to it the same way whenever you want.

Upload a world from your computer

A world is a zip with a folder inside it that holds level.dat. From the Worlds tab:

1. Press Upload world and pick the zip
2. Keep the page open until the progress bar finishes. We upload the file, unpack it, and add the world for you
3. Activate the new world, then restart the server if it's running

The world takes its name from the folder inside the zip, and you never have to rename anything before you upload. If a world already uses that name, we add a number, so a second world arrives as world-2 and a third as world-3, and its Nether and End folders follow the same name. A folder named without Latin letters or digits becomes world. A zip holding several worlds imports all of them in one go. Whichever name a world lands on, we tell you right after the upload.

Moving from Aternos

Your world downloads from the Aternos Worlds page at aternos.org/worlds: select the world, press Download, and a zip of that world lands on your computer. Upload that zip here exactly as it came down, without unzipping or renaming anything.

1. Download the world from the Aternos Worlds page
2. Press Upload world here and pick the zip you downloaded
3. Activate the imported world, then restart the server

Your server already has a world named world, so an Aternos world lands beside it as world-2. Nothing is overwritten, and you pick which one is active.

Create or copy a world

Use Create world to choose a name and optional seed. The new world becomes active and generates at the next start, and your previous world stays available. Use Copy world on a row to copy that world and all its dimensions under a new name without activating it.

Turn on hardcore for a world

In hardcore, each player has one life, and a player who dies becomes a spectator. The difficulty becomes Hard and stays locked while hardcore is on. On Java, hardcore is saved inside the world itself, so the Hardcore field in Settings only applies to worlds created after you turn it on. For a world you already have, set it here.

1. Stop your server.
2. Open Worlds, choose Set hardcore on the world, then turn the switch on or off.
3. Start your server.

A ✓ in the Hardcore column marks each world that has it on. You can turn it off again from the same place at any time, and the server goes back to the difficulty in Settings the next time it starts.

Download a world to your computer

Select Prepare download on the world's row, then Download after it finishes. Stop the server first if you want a clean copy, because a running world writes its files at any moment. The ZIP includes the overworld and all existing Nether and End folders, including the sibling folders used by older Paper and Purpur versions.

The export stays in .serverk-exports until you replace it or delete it from Files. Prepare it again when you want a fresh copy. Exports are excluded from backups. Upload accepts Java worlds only. Native Bedrock worlds belong on a native Bedrock server.

Reset world

Reset world starts the active world over with the same seed. We move the world with its Nether and End to a new name ending in -old, write its seed to level-seed in server.properties, and the next start generates the world again under its own name. Builds, inventories, advancements and stats start over.

1. Open Worlds and press Reset world at the top. It resets the active world, so activate another world first if that's the one you want to reset.
2. Confirm. We stop the server, move the world, and start the server again if it was running.

The old world stays in the list under its name with -old added, such as world-old, or world-old-2 if that name is taken. Activate it to go back, or delete it once you're sure, because it still uses your disk and goes into every backup.

Reset from a copy

Reset from a copy puts the active world back to a copy you keep in the list, builds included. Use it for a map someone built on, such as a lobby or a spawn, where a reset from the seed brings back bare terrain without the builds.

1. Upload the map, use Copy world on its row to keep an untouched copy such as lobby-original, then activate the map itself, not the copy.
2. Whenever you want to start over, press Reset from a copy at the top of Worlds and type the copy's name exactly as the list shows it.
3. Confirm. We stop the server, copy the world you named in place of the active world, and start the server again if it was running.

The copy must stay in the list as it is, so don't activate it or play on it. It takes the disk space of a second world and goes into every backup. The old active world stays in the list as -old, the same as with Reset world. If the copy fails, for example when your disk is full, the active world stays as it was.

Reset the Nether or the End

Reset the Nether and Reset the End delete that dimension completely, and it generates again the next time someone enters it. Handy when everything has been looted, or when you want a fresh dragon.

Delete a world

Delete deletes the world with its Nether and End for good. You can't delete the active world, so activate another one first.

Both world resets keep the old world as -old, but a delete or a Nether or End reset can't be undone, and we don't take a backup before either. Take a backup first, and restore it to bring the world back:

Worlds and backups

Every world on your server goes into the backup. Leave five old worlds parked and your backups grow, take longer, and use up your disk. Delete what you don't need, or download it first and then delete it here.