How to change the world seed in Hytale

Hytale's world creation screen has no seed field, so the seed is changed by hand: you edit one line in config.json. It is easy, but there is one catch that makes many people think "the seed didn't work": areas that have already been generated are not regenerated on their own.

Pick a seed on the map

Make a backup first. To regenerate a world you have to delete its saved chunks, and your builds go with them. Copy the whole world folder somewhere safe before you delete anything.

The safest way: a fresh world

If you just want to play on a seed you like, prepare a brand-new empty world:

Find a seed on the HYSEEDS map: the "Random seed" button shows random worlds, and the layer switches show what is near spawn.
Create a new world in the game and leave it right away.
Close the game and open that world's folder: %AppData%\Hytale\UserData\Saves\<world name> (on a server: universe/worlds/<world name>).
Open config.json and replace the number in the "Seed" line with your seed:
```
"Seed": 1791653948620,
```
Save the file.
In the same folder, delete the chunks folder and, if it exists, the resources folder. A new world has nothing valuable in them yet.
Start the game and load the world: it will be generated from the new seed.

Why delete chunks

A world is generated in pieces (chunks) as you move, and finished pieces are saved to disk. Changing the seed only affects what has not been generated yet. If you keep the saved chunks you get a patchwork of the old and new worlds. Deleting the chunks folder makes the game generate everything again.

Servers

Stop the server before editing: it writes its settings back while running and can overwrite your changes.
A server has two different config.json files: the main one in the server root and one per world in universe/worlds/<world>/. The seed lives in the second one.
Want to keep the old world and start a new one next to it? Create a new world folder and point to it with Defaults.World in the main config.json.

If the world will not start

The most common cause is broken JSON: a missing comma, a stray quote, or the number wrapped in quotes. The seed is a plain number without quotes, followed by a comma when more lines come after it.
Restore the previous value or the file from your backup.
The seed can be any integer.

Check the result

Load the world and compare it with the map: spawn, the temple and nearby camps should be where HYSEEDS shows them. If something does not match, see the FAQ or read how to find the seed of an existing world.