Mods on Your DayZ Server

Installing Mods from the Mods Tab

DayZ mods come from the Steam Workshop for DayZ. Each mod is a folder whose name starts with @, containing packed game files and, usually, a signing key.

1. Open your server's Mods tab and search the Steam Workshop by name, for example "CF" for Community Framework.

2. Install the mod. GameGrid downloads it into your server's files and copies its signing key (.bikey) into the server's keys folder for you.

3. Put your mods in the right order. See Load Order below.

4. Start the server, or Stop and Start it if it is running. Mods are loaded when the server starts, so a mod added while the server runs is loaded from its next start.

DayZ only loads the mods named on its launch line, and GameGrid builds that line from the list on the Mods tab. An @ folder copied in over SFTP or the Files tab is not on that list, so install mods from the Mods tab.

Big mods and community maps

DayZ's community terrains are large. Deer Isle is about 11.7 GB on the Workshop, and several others are over 4 GB — so "how big can a mod be" is a real question on DayZ in a way it is not on most games.

The 20 GiB figure is sized on the largest terrain that actually exists, with headroom for it to grow — so a real community map installs, and something that has run away is still stopped. Over the limit, the install is refused before anything is written, and the banner says what the total was and what the limit is.

Every safety check still runs on every file whatever its size: banned file types and malicious content are refused on a 12 GB terrain exactly as they are on a 400 KB script mod.

Getting a large mod onto your server

A mod file is streamed onto your server's host and checked as it lands: its SHA-256 has to match what was sent, it is written to a temporary name, and it is only moved into place once it verifies. An upload that gets interrupted resumes from where it stopped instead of starting again, and an upload that arrives corrupt is discarded — "nothing was installed" means nothing was installed.

Disk space is checked first

Mods are real files in your server's own folder, and they are not shared between servers: two servers on the same machine running the same 11.7 GB map take 11.7 GB each.

So an install that would fill the machine is refused rather than attempted. The message names the host, how much is free, how much the mod needs, and the headroom the other game servers on that machine need to keep writing their worlds — and it ends with "Nothing has been changed", which is the literal truth. If GameGrid cannot tell how much disk a host has, it refuses too: a mod is written onto the same volume every world on that host lives on, so that is not a risk worth taking on your behalf.

Client & Server and Server Only Mods

Each mod on the Mods tab has a badge that shows how it is loaded:

Most Workshop mods are Client & server mods. Only switch a mod to Server only when its author says it runs on the server alone. Make server only warns you when a mod contains things players need, such as menus, textures or client scripts: players would most likely be kicked or crash.

What players need

Players must load the same Client & server mods as your server, in the same versions. A player without them cannot join.

• DZSA Launcher subscribes players to your server's mods automatically when they join through it.
• Steam Workshop: players can also subscribe to each mod on its Workshop page before joining.

Server only mods need nothing from players. Share your mod list, with links to the Workshop pages, in your community Discord so players know what to get.

Keys and Signature Checks

With Signature Verification set to Full (verifySignatures = 2, the default), a DayZ server checks every mod file a player loads against the keys (.bikey files) in its keys folder. A player whose files do not match is kicked.

• GameGrid copies each installed mod's key into keys, and releases it again when you remove the mod.
• Never delete dayz.bikey from keys: it is Bohemia's own key for the base game.
• Never re-pack a Workshop mod: that breaks its signatures and gets every player kicked.
• Signature or "modified data" kicks have their own guide: Kicked from a DayZ Server.

The Settings tab offers Full, Basic and Off. What each one really costs is in DayZ Server Settings Reference.

When a mod ships no signing key

Some mods — usually older community maps whose authors have moved on — are published without a `.bikey` at all. There is no key you could add, so a server on Full loads the mod happily and then kicks every single player who joins with it. Nothing in DayZ tells you that is what happened.

GameGrid finds it for you instead, and says so before it costs you an evening:

• When you install it, the job banner turns into a warning that does not disappear on its own.
• On the mod's row, permanently, with a red No signing key badge. It is not a dialog you dismiss, because it is not an event — it is the state of your server, and it is true again at every start.
• In the start log, at the moment the server is launched. That one also catches a mod folder you uploaded by hand, and a key that was in keys when you installed the mod and is not there now.

The warning names the cause — the mod ships no key, its keys folder is empty, or its key has a file name the platform will not write — and then gives you the two honest options:

• Ask the author for the `.bikey`. That is the fix that keeps your server protected. Some mods are abandoned and their authors will never ship one.
• Or lower Signature Verification on the Settings page, knowing what it costs: it turns the check off for every mod on that server and every player, not just this one. GameGrid will not do it for you — there is deliberately no button here that lowers it, because a one-click fix would be a one-click security downgrade.

If neither suits, remove the mod. A mod that is installed and cannot be joined is the one state worth not leaving your server in.

Server only mods are never affected. A -servermod= mod is not sent to players at all, which is why GameGrid's own server-side mod is unsigned and still works on a server set to Full.

Load Order

The list on the Mods tab is the load order: the mod at the top loads first. A mod must load after anything it depends on. Get this wrong and the server fails to start with "requires addon" errors, or crashes.

Move mods with the arrows on each one. The usual order, top to bottom:

1. Frameworks: @CF (Community Framework), @Dabs Framework.

2. Big core mods: for example @DayZ-Expansion-Core and then the Expansion modules in the order their documentation gives.

3. Content mods: weapons, vehicles, clothing, buildings.

4. Admin tools and small tweaks.

When a mod page says "load after X", follow it. A new order is used from the next time the server starts.

Mission Files: The Step People Forget

On any DayZ server, installing a mod makes its items exist. It does not make them spawn. Mods that add loot, vehicles or map objects usually ship extra mission files that have to be merged:

• types.xml entries so the items spawn as loot. See DayZ Loot Economy Explained.
• events.xml and cfgeventspawns.xml entries for vehicles and events. See Vehicles, Heli Crashes and Dynamic Events.
• Configuration files in profiles/, which many mods create on their first start.
• A mission folder for map mods. See Changing Your DayZ Map.

Follow each mod's own instructions for these files, and take a manual backup on the Backups tab before merging anything.

Mod Updates

Mods come from the Steam Workshop, so their updates follow the Workshop. When a mod author publishes an update, players' Steam clients update it, and a server still running the old version kicks those players for a mismatch.

The Mods tab marks a mod Update available when the Workshop has a newer version. A server restart does not fetch a mod update. Updating is its own step, done while the server is stopped: Stop, Update the mod, then Start.

After a DayZ patch, mods often break until their authors update them. See DayZ Version Mismatch and Server Updates.

Disabling and Removing a Mod

• Disable keeps a mod installed but leaves it out from the next start. Enable puts it back.
• Remove deletes the mod's folder and releases its key. Stop the server before removing a mod: a running DayZ server keeps its mod files open.

Take a manual backup on the Backups tab before you do either. On a server that already has a saved world, taking a mod out can reset items and objects that were saved while it was loaded — including plain vanilla ones the mod never added. This is the single most damaging thing you can do to a DayZ world by accident, and nothing warns you afterwards.

Why it happens, what it affects and how to avoid it: Removing a Mod Can Take Your World With It.

Tuning Without Mods

Plenty can be changed without any mods:

• Loot, vehicles and events in the mission files. See DayZ Loot Economy Explained.
• Time of day and weather. See Day Length, Night Speed and Weather.
• Player management from the Console tab. See BattlEye RCon and the Console Tab.

For teleporting, item spawning and other admin menus, see Admin Tool Mods: Community Online Tools and VPP.