# How to Set the World Seed on Your Core Keeper Server (/docs/core-keeper/seed-guide)



import { Step, Steps } from 'fumadocs-ui/components/steps';

Setting a Seed [#setting-a-seed]

Via startup parameter:

```
-worldseed 12345
```

Or in `ServerConfig.json`:

```json
"worldSeed": 12345
```

A value of `0` means random seed generation.

Generating a New World with a Different Seed [#generating-a-new-world-with-a-different-seed]

<Steps>
  <Step>
    Change the seed value (`-worldseed` or `worldSeed` in `ServerConfig.json`).
  </Step>

  <Step>
    **Also change the `world` index** to an unused slot (e.g., from `0` to `1`).
  </Step>

  <Step>
    Restart the server.
  </Step>
</Steps>

> ⚠️ **Important:** Changing the seed without changing the world slot does nothing — the server loads the existing world from that slot. You must use an empty slot for a new seed to take effect.

World Slots [#world-slots]

Core Keeper supports **30 world slots** (index 0–29). Each slot is a separate world save.

Related Guides [#related-guides]

* [Server Configuration](/docs/core-keeper/server-config)