RuneLite Plugin Tester

Lets you start the official RuneLite client with custom start arguments (--developer-mode, etc.) without having to compile RuneLite from source in an IDE.

How it works

The Jagex Launcher wraps RuneLite and doesn't expose command-line arguments. Normally you'd need to clone the RuneLite repo and run it from an IDE to pass flags like --developer-mode. DevLauncher loads the official client jars from ~/.runelite/repository2/ and starts the client with whatever arguments you want — no IDE required.

Only tested on Windows.

Prerequisites

• JDK 11+ (Adoptium)

Jagex Accounts

If you use a Jagex account, see Using Jagex Accounts for the required setup.

Setup

1. Populate the repository

Run RuneLite at least once (however you normally launch it — standalone launcher or Jagex Launcher). This downloads the client jars to ~/.runelite/repository2/ and creates the sideloaded-plugins directory.

2. Compile DevLauncher

Windows:

compile.bat

Linux / Mac:

chmod +x compile.sh
./compile.sh

This creates DevLauncher.jar in the current directory.

3. Build your plugin

A RuneLite plugin is a standard Java project built with Gradle. The source lives under src/main/java/ in a package like com.yourname.youplugin/.

Your build.gradle needs the RuneLite client dependency:

repositories {
    maven { url = 'https://repo.runelite.net' }
    mavenCentral()
}

dependencies {
    compileOnly 'net.runelite:client:latest.release'
}

To build:

cd your-plugin
./gradlew build

The output jar is at build/libs/your-plugin-*.jar (the exact name depends on your build.gradle settings). This jar contains your compiled plugin and can be sideloaded.

4. Install the plugin

Copy the jar to the sideloaded plugins directory:

copy "build\libs\your-plugin.jar" "%USERPROFILE%\.runelite\sideloaded-plugins\"

For example: C:\Users\Roberto I\.runelite\sideloaded-plugins\

5. Launch

java -jar DevLauncher.jar

The RuneLite client starts with developer mode enabled, and your plugin loads automatically.

Updating DevLauncher

Rebuild after modifying DevLauncher.java:

compile.bat