Install and run a server

This page takes you from an empty machine to a local server running the default gamemode, with you standing in it. It takes about ten minutes the first time.

What you need

What	Why	Needed to
Kingdom Come: Deliverance II	The client runs inside the game. A Steam, GOG or any other copy works	Join a server
A KCDC release	The launcher, the client and the dedicated server for Windows and Linux	Run anything
Node.js 22 or newer, with npm	Installs dependencies and runs the TypeScript compiler	Build the default gamemode or any TypeScript resource
An editor	Visual Studio Code autocompletes the whole API in a TypeScript resource	Writing code

Note

The server does not need Node.js to run: it carries its own JavaScript runtime. Node only compiles TypeScript, so you can build on your own machine and upload the result.

1. Get a release

A release is one archive. Unpack it anywhere, not inside the game folder (nothing is ever copied there):

KCDC/
  client/            KCDCLauncher.exe and the mod itself
  server/            KCDCServer.exe for Windows, with its own resources/
  server-linux/      KCDCServer for Linux, with its own resources/
  resources/         the default gamemode on its own, to edit or upload
  README.txt

Each server folder reads resources from the resources/ folder next to its binary. The top-level resources/ is a spare copy for hosting elsewhere; the guides use the one inside server/.

Caution

Unpack the complete archive so the launcher has its dependencies. In 1.6.6, it resolves updates from the installed build through the update service; the archive’s channel file is only an initial hint for a fresh installation.

2. Install Node.js and npm

1. Install Node.js 22 or newer. The LTS installer is fine.
2. Open a new terminal. node --version should print v22 or later, and npm --version should print a version number.

The 1.6.6 default game mode and optional playground use npm and include a package-lock.json. They do not require pnpm or Corepack. Your own resources can use the package manager you prefer.

3. Build the gamemode

A release ships the gamemode as TypeScript source. Until you build it, the server starts but answers no commands.

In server/resources/kcdc-gamemode/

npm ci
npm run build

npm ci installs the locked compiler and API declarations, @kingdomsconnected/types at your release’s version. npm run build compiles the server and client halves as two programs. You now have dist/server/index.js (what the server runs) and dist/client/index.js (what every player’s game runs). Use TypeScript explains the setup.

The mafiahub block in package.json tells the server which files to run and send to players; see Resource manifest and lifecycle.

4. Start the server

From the server/ folder:

Windows

.\KCDCServer.exe

Linux (from server-linux/)

./KCDCServer

The first start writes a server.json with every setting and its default. Look for the gamemode’s two lines in the log (the command count varies):

[kcdc-gamemode] debug panel answering; clients open it with F4 or /ui
[kcdc-gamemode] ready with 20 commands

The server uses UDP 27015 and TCP 27016; a server on your own machine needs nothing opened. See Ports.

5. Join it

1. If your copy of the game is on Steam, start Steam.
2. Run client/KCDCLauncher.exe. The game starts with the multiplayer menu.
3. Choose Quick connect. It connects to 127.0.0.1 on port 27015, where your server listens.

The launcher finds the game on its own the first time:

Your copy	What the launcher does
Steam, with Steam running	Asks Steam where the game is installed. Nothing to pick
Microsoft Store / Xbox app (PC Game Pass)	Detects the installed package after trying Steam
GOG or a copy not detected automatically	Opens a file dialog. Pick GOG’s Bin\Win64MasterMasterGogPGO\KingdomCome.exe or Steam’s Bin\Win64MasterMasterSteamPGO\KingdomCome.exe

The launcher saves the game path in client/KCDC_launcher.json, so later launches use the same copy. A manually selected executable takes precedence over automatic store detection. Delete that file to choose again. The launcher also registers kcdc:// links for the current Windows user on startup.

The game loads the level named in server.json, and the gamemode greets you in chat.

Skip the menu

Pass a server link to the launcher to connect straight away. Handy for two clients on one machine, each with its own nickname:

In client/

.\KCDCLauncher.exe "kcdc://127.0.0.1?nickname=Tester"

6. Try some commands

Open chat with T:

Type	What happens
/help	Lists every command the gamemode registers
/horse	Spawns a horse in front of you
/world hour 21	Moves the shared clock to nine in the evening, for everyone
/dialogue	Opens a sample conversation in the game’s dialogue list
/quest give errand "Deliver the letter"	Writes a quest into everyone’s journal

Press F4 for the debug panel: live stats, the world clock, who is connected and a command box. Esc hands the keyboard back to the game while the panel stays open.

7. Change something and reload

1. Keep both compilers watching your changes:

   In server/resources/kcdc-gamemode/

   npm run dev

2. Edit src/server/index.ts, for example the welcome line in the playerSpawned handler.

3. In the server console (the server’s window, not game chat), reload the resource:

   Server console

   ensure kcdc-gamemode

   ensure reloads a running resource from disk and pushes new client files to everyone connected. Reconnect to see the new welcome.

npm run dev watches both halves in one terminal. It recompiles files but does not reload the running resource; use ensure after a successful compile. Press Ctrl+C to stop both watchers. Use npm test to build both halves and run the game mode’s automated tests. The separate npm run watch and npm run watch:client commands remain available.

Compilation followed by ensure works for your own resources too. Console commands lists the others, such as stop, start and refresh.

Troubleshooting

error TS2304: Cannot find name 'Player' (and hundreds like it)

The compiler cannot find the declarations. Run npm ci in the game mode folder first, then build again.

The build fails on a few specific methods

Your declarations and your release are different versions. Check that @kingdomsconnected/types in the game mode’s package.json is your release’s version. Use the matching release’s package files and run npm ci again. If you deliberately edit dependencies, run npm install to update the lockfile before building.

The server starts, but commands do nothing

With no compiled gamemode, nothing listens for commands, so /help is silently ignored. Check that resources/kcdc-gamemode/dist/server/index.js exists, and look in the server log for a kcdc-gamemode line near startup: a missing file or a script error is reported there.

npm: command not found

Install Node.js with npm selected, then open a new terminal so its updated PATH is available.

The launcher cannot find the game

With a Steam copy, start Steam before the launcher, which asks Steam where the game is installed. The launcher next tries the installed Microsoft Store / Xbox app package. If it still asks, pick KingdomCome.exe in the dialog: Steam uses Bin\Win64MasterMasterSteamPGO\ and GOG uses Bin\Win64MasterMasterGogPGO\ under the game folder. Cancelling the dialog closes the launcher.

If the game moved, or you picked the wrong copy, delete KCDC_launcher.json next to the launcher and it will ask again.

Related

• Write your first resource: the next step, a resource of your own next to the gamemode.
• Let players connect: the server browser and remote hosts.
• Run a dedicated server: arguments, ports and console commands.
• server.json settings: every setting the first start wrote.