How to make a Minecraft Java server Hardcore.

What Hardcore changes

On a Paper server, the hardcore property controls the Hardcore death behavior. When it is enabled, a player who dies is placed into spectator mode instead of respawning normally.

Hardcore is different from simply setting difficulty=hard. Hard difficulty changes combat and survival pressure; the Hardcore property changes what happens after death.

Enable Hardcore from the ChunkArc panel

1. Stop the server completely. Wait until the Console shows that the process is offline.
2. Download an important-world copy. The Free Beta does not promise automatic customer backups.
3. Open Files. Select server.properties in the server root.
4. Find the Hardcore property. Change hardcore=false to hardcore=true.
5. Set the intended difficulty. Use difficulty=hard when you want the normal Hardcore challenge.
6. Save and start once. Watch the first startup in Console and wait for the server to finish loading.

Verify that it worked

Reopen server.properties and confirm the value remains true. Join with a test account only when you understand that a real death can place that player into spectator mode.

If the value changes back, make sure the server was stopped before editing and that you saved the correct file. Do not use /reload as a substitute for a full restart.

What about an existing world?

Do not delete an existing world merely to edit the property. Preserve a copy, enable the setting while offline and verify the behavior after the restart. Existing builds and player progress should be treated as important data before any rule change.

How to turn Hardcore off again

Stop the server, change the property back to hardcore=false, save and restart. Players already left in spectator mode may still need an administrator to restore their game mode according to your server rules.