MelonLoader

MelonLoader is a free mod loader for Unity games, suited to players adding mods and plugins and developers working on them. Its support for both Mono and Il2Cpp makes it a flexible choice within Unity, but Android and Oculus Quest support is still a work in progress.

Overview

MelonLoader injects into compatible Unity games and supports games built on either Mono or Il2Cpp. Mods and plugins live in separate Mods and Plugins folders in the game installation directory; load-order control and dependency handling help keep multi-mod setups manageable. That makes it useful for players whose games have an active mod ecosystem, but it is not a general-purpose loader for games built on other engines.

Users can follow an installer guide or install manually from a release archive. Logs go to a MelonLoader/Logs folder inside the game directory, giving players and developers a concrete place to look when troubleshooting. Debug mode is aimed at developing and debugging the loader, mods, and plugins, so its value is greatest for people who build or maintain add-ons rather than players who only install them.

Key features

• Mono and Il2Cpp coverage: Supports both Unity runtime types, avoiding the need to choose a loader solely on that distinction.
• Organized mod and plugin loading: Separate folders, load-order control, and dependency handling suit setups with multiple add-ons, though users still need to manage files in the game directory.
• Installation choices: An installer guide and manual release-archive instructions offer two routes, useful for different preferences but requiring installation within each game's directory.
• Developer diagnostics: Debug mode supports work on MelonLoader, mods, and plugins. The Mono debug server defaults to 127.0.0.1 on port 55555.
• Logs and offline generation: Game logs are written to MelonLoader/Logs, and the Il2Cpp Assembly Generator can be configured to run without contacting its remote API.

Pricing

MelonLoader costs nothing under the Apache License 2.0. There is no paid tier or trial to weigh; the free plan is the whole offer, making it a straightforward option for players who want Unity mod loading without a software charge.

Platforms

MelonLoader supports Windows, Linux, macOS, Android, and Oculus Quest, but the latter two are marked work in progress. Linux guidance covers WINE, Steam Proton, and native use, giving Linux users several documented paths. On Windows, a proxy DLL loads MelonLoader when the game starts; that mechanism is Windows-only. For Il2Cpp games, the listed requirement is the .NET 6.0 Desktop Runtime, which is installed automatically on Windows.

Who it's for

MelonLoader is the right fit for players modding Unity games that use Mono or Il2Cpp, especially when they need plugin support, load-order control, or dependency handling. It also suits developers who want debug mode and a defined log location. Players on Android or Oculus Quest should treat support as experimental in status, while anyone modding a non-Unity game should look elsewhere.

Pros and cons

• Pros: Free under Apache License 2.0; supports both Mono and Il2Cpp; offers plugin loading, load-order control, and dependency handling; provides installer and manual installation guidance.
• Cons: Restricted to Unity games; Android and Oculus Quest support remains in progress; Windows proxy loading does not apply on other platforms; Il2Cpp games require the .NET 6.0 Desktop Runtime.

Alternatives

For Stardew Valley players, SMAPI is another free option, though Linux, macOS, Windows, and Steam Deck users need Stardew Valley 1.6.14 or later. BepInEx is also free and offers manual installation with stable and bleeding-edge builds; consider it if those builds suit your workflow better. Satisfactory Mod Loader is a free alternative for its supported game, with no required dependencies and Windows client and server plus Linux server support.

Hell2Modding is a free alternative for macOS and Windows. MWSE is a free, open-source option for Linux and Windows, licensed under GNU GPL with no warranty. Everest is a free alternative with Linux, macOS, Windows, and API platform support. Northstar is free and supports Linux and Windows, while ModTek is free and supports Windows, macOS, and Linux. Browse the Game Mod Loaders list for more options.

Verdict

Choose MelonLoader if you want a free loader for a Unity game and value support for both Mono and Il2Cpp, plus plugin and debugging tools. Its clearest advantage is that broad Unity runtime coverage paired with organized add-on loading. Look elsewhere if your game is not built on Unity or if you need finished Android or Oculus Quest support.