> ## Documentation Index
> Fetch the complete documentation index at: https://docs.wasabihosting.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Install Steam Workshop Mods on a DayZ Server

> Add Steam Workshop mods to your DayZ server hosting - upload @Mod folders, set the -mod startup parameter, manage .bikey signature keys, and update mods.

Mods are where DayZ servers come alive — new weapons, base building, traders, whole new maps. DayZ mods come from the Steam Workshop and follow a simple pattern on the server: each mod is an `@ModName` folder, loaded through the `-mod=` startup parameter, and signed with a key the server must trust. This guide covers the full workflow.

## How DayZ Mods Work

Three pieces must line up for a modded server:

1. **The mod files** — an `@ModName` folder in the server's root directory (containing the mod's `addons/` PBOs).
2. **The load order** — the `-mod=` startup parameter listing every mod, separated by semicolons.
3. **The signature key** — each mod ships a `.bikey` file that must be copied into the server's `keys/` folder, because `verifySignatures = 2` makes the server reject unsigned content.

And critically: **every player must run the exact same mods** (same versions) or they can't join. The [DZSA Launcher](/games/dayz/join-server) automates this on the client side.

## Installing a Mod

<Steps>
  <Step title="Get the mod files from the Workshop">
    Subscribe to the mod on the Steam Workshop using your own DayZ client. Steam downloads it to your PC — find it in `steamapps/common/DayZ/!Workshop/@ModName` (or `steamapps/workshop/content/221100/<mod-id>`).
  </Step>

  <Step title="Upload the @ModName folder to the server">
    Upload the entire `@ModName` folder to your server's **root directory** (next to `serverDZ.cfg`) via SFTP — see [File Management](/server/file-management). Mods can be gigabytes, so SFTP beats the browser uploader here.
  </Step>

  <Step title="Copy the .bikey into keys/">
    Inside the mod folder you'll find a `keys/` (sometimes `key/`) subfolder containing one or more `.bikey` files. Copy each `.bikey` into the **server's** `keys/` folder. Skip this and every client gets kicked by signature verification.
  </Step>

  <Step title="Add the mod to the startup parameters">
    In the [Game Panel](https://panel.wasabihosting.com), open your server's **Startup** tab and add the mod to the `-mod=` parameter, semicolon-separated, no spaces:

    ```
    -mod=@CF;@Community-Online-Tools
    ```
  </Step>

  <Step title="Restart and verify">
    Restart the server and watch the console. The mod list is printed during startup; errors about missing PBOs or keys show up here immediately.
  </Step>
</Steps>

## Load Order Matters

Mods load left to right, and **frameworks must load before the mods that depend on them**. `@CF` (Community Framework) is the classic example — it must come first:

```
-mod=@CF;@Dabs Framework;@DayZ-Expansion-Core;@DayZ-Expansion;@Community-Online-Tools
```

Each mod's Workshop page lists its dependencies — anything listed as *required* must be installed too, and placed earlier in the chain.

## Popular Foundation Mods

| Mod                              | What it does                                                                                                                                           |
| -------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------ |
| **CF (Community Framework)**     | The shared library huge numbers of mods depend on. Install it first, load it first.                                                                    |
| **Community Online Tools (COT)** | The standard in-game admin toolkit — teleport, item spawning, player management. See [Admin Tools](/games/dayz/admin-tools).                           |
| **DayZ Expansion**               | A modular overhaul — vehicles including helicopters, base building, traders, quests, and a new map UI. Start with `Core` and add the modules you want. |

Community maps like **Namalsk** and **Deer Isle** are installed the same way — they're mods that also add a mission you reference in `serverDZ.cfg` (see [Server Configuration](/games/dayz/server-configuration)).

## Updating Mods

When a mod updates on the Workshop, clients get the new version automatically — your server doesn't. Until you update it, players are kicked for version mismatch.

<Steps>
  <Step title="Let Steam update your local copy">
    Launch Steam; subscribed mods update automatically in your local Workshop folder.
  </Step>

  <Step title="Re-upload the changed mod">
    Replace the server's `@ModName` folder with the updated one via SFTP.
  </Step>

  <Step title="Refresh the key if it changed">
    Some updates ship a new `.bikey`. Copy any new key into the server's `keys/` folder (old keys can be removed once no mod uses them).
  </Step>

  <Step title="Restart">
    Restart the server. Done.
  </Step>
</Steps>

<Tip>
  Take a [backup](/server/backups) before big mod updates — mods that add items interact with your economy files, and rolling back is much easier than untangling broken persistence.
</Tip>

## Common Errors

<AccordionGroup>
  <Accordion title="Players kicked immediately after connecting (signature verification)">
    A mod's `.bikey` is missing from the server's `keys/` folder. Check that every mod in `-mod=` has its key present, then restart.
  </Accordion>

  <Accordion title="Server won't start or crashes on startup">
    Usually a wrong load order (dependency loaded after the mod that needs it) or a typo in `-mod=` — folder names must match exactly. Check the console output; it names the mod it choked on.
  </Accordion>

  <Accordion title="'PBO not part of the server data' on the client">
    The player has a mod (or version) the server doesn't. Point them at the DZSA Launcher, which syncs the exact mod set automatically.
  </Accordion>

  <Accordion title="Mod uploaded but not loading">
    Confirm the folder sits in the server root (not inside another folder), and that the name in `-mod=` matches the folder name character for character. On Linux-based servers, file name casing can matter — if a mod inexplicably fails to load, lowercase file names are a known fix; our support team can help.
  </Accordion>
</AccordionGroup>

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