How to install Arsenic

Requirements

• Minecraft 1.8.9 (Vanilla, Forge or Lunar Client with OptiFine)
• A JDK installed (8, 17 or 21 all work for running the jar)
• The latest Arsenic jar

Vanilla or Forge

1. Start Minecraft 1.8.9 and get to the main menu.
2. Double-click the downloaded Arsenic jar.
3. Pick your running game in the window that appears.
4. Press Inject.

Lunar Client

1. Double-click the downloaded Arsenic jar.
2. Click inject into lunar. This closes Lunar if it is open.
3. Reopen Lunar and play 1.8.9 with OptiFine.

Where is my data?

Configs, addons, themes and everything else Arsenic saves live in one Arsenic folder in your home directory — C:\Users\<name>\Arsenic on Windows, ~/Arsenic elsewhere. It is the same whichever launcher you use. An Arsenic folder left in a game folder by an older version is copied there the first time.

Build from source

1. Install JDK 8 and set JAVA_HOME (Gradle 4.9 and ForgeGradle 2 only run on JDK 8).
2. Clone the repository.
3. Run setup.bat (Windows) or setup.command (macOS/Linux). First run downloads Minecraft and Forge and takes a few minutes.
4. Open the generated Arsenic.ipr in IntelliJ. If imports are unresolved, run gradlew idea and reopen it.
5. Check the build with gradlew build.

Stuck? Contact @kv.dev on the Discord.