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Building Locally

By the end of this guide, you will have Unciv running locally from code, so you can make changes and test them locally.

With Android Studio

  • Install Android Studio - it's free and awesome! Be aware that it's a long download!
  • Install Git, it's the way for us to work together on this project. UI is optional, Android Studio has good Git tools built in :)
  • Getting the code
    • Create a Github account, if you don't already have one
    • Fork the repo - this will create a "copy" of the code on your account, at<YourUsername>/Unciv
  • Load the project in Android Studio
    • File -> New -> Project from Version Control -> GitHub
    • Enter your GitHub username and password
    • Select the repository and hit clone - The GitHub repo will be created as a new project in Android Studio.
  • Gradle will attempt the initial sync. If this is your first time with Android Studio, this may require you to accept the Android Build-tools licenses, which works differently on every device, so search for your OS-specific solution.
    • A new install may not be able to do the initial sync - this comes in the form of Unable to find method ''void<init>(java.nio.channels.SeekableByteChannel)'' errors when you try to sync. If you have this problem go into File > Settings > Appearance & Behavior > System Settings > Android SDK
      • Click "SDK Platforms"
      • Click "Android 13 (Tiramisu)" image (Optionally, you can save some space by selecting 'Show Package Details' and choosing the Platform SDK only, without Sources or system Images)
      • Click "SDK Tools"
      • Select "Show Package Details" in the bottom right
      • Choose version 34.0.0 under "Android SDK Build-Tools"
      • Click "Apply"
      • Restart Android Studio
  • In Android Studio, Run > Edit configurations (be sure the Gradle sync is finished successfully first).
    • Click "+" to add a new configuration
    • Choose "Application"
    • Give the configuration a name, we recommend "Desktop"
    • Set the module classpath (the box to the right of the Java selection) to Unciv.desktop.main (Unciv.desktop for Bumblebee or below), main class to and $ProjectFileDir$/android/assets as the Working directory, OK to close the window
      • It may be useful to set some VM options - activate the field in the run config editor with Alt-V or via the Modify Options menu, then add -Xmx4096m -Xms256m -XX:MaxMetaspaceSize=256m to allow a debugged game a little more memory. Or, use the -DnoLog= or -DonlyLog= options to control console logging. See the Log.kt comments for details.
      • If you get a ../../docs/ (No such file or directory) error that means you forgot to set the working directory! image
  • Select the Desktop configuration (or however you chose to name it) and click the green arrow button to run! Or you can use the next button -the green critter with six legs and two feelers - to start debugging.
  • A few Android Studio settings that are recommended:
    • Going to Settings > Version Control > Commit and turning off 'Before Commit - Analyze code'
    • Settings > Editor > Code Style > Kotlin > Tabs and Indents > Continuation Indent: 4 image
    • Settings > Editor > General > On Save > Uncheck Remove trailing spaces on: [...] to prevent it from removing necessary trailing whitespace in for translation files image
    • Right-click the android/assets/SaveFiles folder, "Mark directory as" > Excluded
    • If you download mods do the same for the android/assets/mods folder and any other files you may create while testing that do not belong in the public project.
    • This disables indexing for performance.

Unciv uses Gradle to specify dependencies and how to run. In the background, the Gradle gnomes will be off fetching the packages (a one-time effort) and, once that's done, will build the project!

Unciv uses Gradle 7.5 and the Android Gradle Plugin 7.3.1. Can check in File > Project Structure > Project

Note: advanced build commands (as described in the next paragraph), specifically gradlew desktop:dist to build a jar, run just fine in Android Studio's terminal (Alt+F12), with most dependencies already taken care of.

Without Android Studio

  • Ensure you have JDK 11 or higher installed
  • Clone the project (see above initial steps)
  • Open a terminal in the Unciv folder and run the following commands


  • Running: gradlew desktop:run
  • Building: gradlew desktop:dist

Linux/Mac OS

  • Running: ./gradlew desktop:run
  • Building: ./gradlew desktop:dist

If the terminal returns Permission denied or Command not found on Mac/Linux, run chmod +x ./gradlew first. This is a one-time procedure.

If you get an error that Android SDK folder wasn't found, install it by running:

sudo apt update && sudo apt install android-sdk (Debian, Ubuntu, Mint etc.)

Then, set the SDK location in the file by adding:

sdk.dir = /path/to/android/sdk - for example, /usr/lib/android-sdk

If during initial launch you get an error that the JDK version is wrong, install the JDK from here.

Note: Gradle may take up to several minutes to download files After building, the output .JAR file should be in /desktop/build/libs/Unciv.jar

For actual development, you'll probably need to download Android Studio and build it yourself - see above :)

Debugging on Android

Sometimes, checking things out on the desktop version is not enough and you need to debug Unciv running on an Android device. For an introduction, see Testing android builds.

Next steps

Congratulations! Unciv should now be running on your computer! Now we can start changing some code, and later we'll see how your changes make it into the main repository!

Now would be a good time to get to know the project in general at the Project Structure overview!

Unit Tests

You can (and in some cases should) run and even debug the unit tests locally.

  • In Android Studio, Run > Edit configurations.
    • Click "+" to add a new configuration
    • Choose "Gradle" and name the config, e.g. "Unit Tests"
    • Under "Gradle Project", choose "Unciv" from the dropdown (or type it), set "Tasks" to :tests:test and "Arguments" to --tests "com.unciv.*", OK to close the window.
  • Select the "Unit Tests" configuration and click the green arrow button to run! Or start a debug session as above.


Detekt checks for code smells and other linting issues. To generate Detekt reports:

  • Download detekt-cli (the zip file) and unzip it
  • Open a terminal in the Unciv root directory and run one of the following commands to generate the report. NOTE: If you're using Windows, replace detekt-cli with detekt-cli.bat.
    • For warnings: PATH/TO/DETEKT/detekt-cli --parallel --report html:detekt/reports.html --config .github/workflows/detekt_config/detekt-warnings.yml
    • For errors: PATH/TO/DETEKT/detekt-cli --parallel --report html:detekt/reports.html --config .github/workflows/detekt_config/detekt-errors.yml
  • The report will be generated in detekt/reports.html


The simple multiplayer host included in the sources can be set up to debug or run analogously to the main game: - In Android Studio, Run > Edit configurations. - Click "+" to add a new configuration - Choose "Application" and name the config, e.g. "UncivServer" - Set the module to Unciv.server.main (Unciv.server for Studio versions Bumblebee or below), main class to and <repo_folder>/android/assets/ as the Working directory, OK to close the window. - Select the UncivServer configuration and click the green arrow button to run! Or start a debug session as above.

To build a jar file, refer to Without Android Studio and replace 'desktop' with 'server'. That is, run ./gradlew server:dist and when it's done look for /server/build/libs/UncivServer.jar