Kotlin for Forge
Adds a Kotlin language loader and provides some optional utilities.
About this Mod
Used to make mods with the Kotlin programming language. Works by shading the Kotlin libraries, providing KotlinLanguageProvider to load @Mod object declarations, providing AutoKotlinEventBusSubscriber to load @EventBusSubscriber declarations, and providing useful utility functions and constants.
As of Kotlin for Forge 1.8.0, this provides Kotlin 1.4.21, Kotlin coroutines 1.4.2, Kotlin JSON serialization 1.0.1, and Jetbrains annotations 20.1.0.
If you're not a mod developer, this is a dependency mod.
Unlike Kottle, this library (as of 1.2.0) provides its own implementation of IEventBus that supports IEventBus#addListener and IEventBus#addGenericListener with function references.
Information for how to implement can be found here.
You do not have to use the language loader or any of the features Kotlin for Forge provides, you can just use it for the bundled Kotlin libraries.
If you'd like to ask for help or suggest something, feel free to do so on the Kotlin for Forge discord server.
Available Versions
How to Install Kotlin for Forge on Your Server
Order Server
Order a Minecraft Java server with at least 3 GB RAM (4 GB recommended).
Set forge Loader
In the panel under "Egg", select the forge loader and matching Minecraft version (26.2).
Install Mod
Open the mod browser in the dashboard and search for "Kotlin for Forge". Click "Install" – done! Alternatively, upload the .jar via SFTP to the /mods folder.
Compatibility
Mod Loaders
Minecraft Versions
26.2, 26.1.2, 26.1.1 (+44 more)
Server-side
~ OptionalRecommended RAM
4 GB(min. 3 GB)Frequently Asked Questions
Kotlin for Forge server crashes on startup – what to do?
Most common cause: wrong forge version or insufficient RAM. Check the server log (latest.log) for "OutOfMemoryError" or "Mixin" errors. With Mado Hosting: ensure at least 3 GB RAM is allocated and the loader matches the mod version (26.2). You can switch loaders with one click in the panel.
Is Kotlin for Forge compatible with forge and neoforge?
Kotlin for Forge officially supports forge, neoforge for Minecraft 26.2, 26.1.2, 26.1.1. The Mado dashboard automatically detects incompatible loader combinations.
Server lagging with Kotlin for Forge – how to optimize performance?
Recommended RAM: 4 GB (per 8 players). Use /spark profiler to check if Kotlin for Forge consumes the most tick time. Common fixes: reduce server view-distance to 8-10, install "performant" or "starlight" as supplementary mods on Forge. With Mado Hosting, your server runs on NVMe SSDs with dedicated CPU cores for minimal latency.
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