URKit

URKit lets you write mods for Windows x64 Unity games in plain C++. You point it at a game, and it hands you a CMake project that already builds. From there you can find and change game objects, call the game's own methods, hook functions, react to scene changes, and draw an ImGui overlay. It works with both Mono and IL2CPP games.

Unreal Engine support is on the way, but it isn't ready yet. See where it stands.

What's in a release

• urk-sdk.exe makes a new mod project for a game.
• urk-updater.exe brings an existing project up to date without touching the files you wrote.
• version.dll, winhttp.dll, winmm.dll and dwmapi.dll are the loaders. You only need one of them: the one the game actually loads. version.dll is a good first try. If Windows loads its own copy first (some games get a compatibility shim that does), try dwmapi.dll.
• URKitInjector.dll is a loader for when you'd rather inject it yourself than drop a proxy next to the game.
• urk-dev-mcp.exe and URKitDevBridge.dll are optional. They let AI coding assistants build, deploy and inspect your mod.

The loader goes next to the game's executable, and your built mods go in a Mods folder beside it. Install just one loader and keep its name as is.

Quick start

./urk-sdk.exe --game-exe C:\Games\Example\Example.exe --backend auto --name MyMod
cd <GameDir>\urk-sdk-output\MyMod\project
cmake --preset clang-debug
cmake --build --preset clang-debug --parallel

--backend auto works out whether the game is Mono or IL2CPP for you. The build puts a debug DLL straight into the game's Mods folder.

You'll need CMake 3.28 or newer, Ninja, and either LLVM/Clang or MSVC (VS 2022 Build Tools or newer). Prefer cl.exe? Use msvc-debug. When you're ready to share your mod, build with clang-release or msvc-release.

Now start the game and open URKit_logs.log next to its executable. You should see your mod load. No log file at all usually means the game doesn't load the loader you picked, so try one of the others.

Unreal Engine (work in progress)

We're working on Unreal support, and honestly it's not ready for real mods yet. Unity has an API we can ask about the game; Unreal doesn't, so URKit has to find everything on its own while the game runs. That part works, but so far it has only been tried on two games, and the second one already turned up bugs. Here's where things stand:

What	Status	Notes
Finding the engine in a running game	Works	Tried on a UE 5.8 game and a UE 5.4 game
Calling game functions, hooking ProcessEvent	Works	The 5.4 game needed a fix first
Map load / map change events	Works
update() every frame	Buggy	In quiet scenes like a main menu it can drop to about once a second
Typed headers from the game (DumpTypes)	Works on 5.8	Not tried on other versions yet
Numbers, objects, structs, FString, FName, TArray	Works on 5.8
TSet and TMap	Mostly works	If an edit fails halfway, the container can be left broken
FText	5.8 only	Turned off on 5.4 for now
Enums by name, soft and weak references, delegates	Works on 5.8
Sparse delegates, interfaces, lazy pointers	Not yet
Engines older than 4.25	Not supported

If you want to poke at it anyway: put the loader next to the game's -Win64-Shipping.exe, add this to URKit_config.ini in the same folder, and play through the maps you care about:

[Unreal]
DumpTypes=1

Then make a project with --backend unreal. The generated sdk/unreal/README.md explains the rest. If something breaks, an issue with your URKit_logs.log attached helps a lot.

Learn the API

New to URKit? Start with Getting Started. It walks you through a real mod, from printing your first log line to reading and changing game state.

If you'd rather watch, there's the URKit SDK Tutorial Series on YouTube.

Once you know the basics, the SDK Handbook is the full reference. It covers finding objects, threading rules, hooks, rendering and highlights, caching, and what to check when something doesn't work. Its first chapter is about updating projects, including hand-patched ones and running the updater from a script.

Curious how URKit works inside? Read ARCHITECTURE.md. The AI-assistant server has its own page in docs/DEV_MCP.md.

Building URKit yourself

You'll need the same tools as for a mod project. For the MSVC presets, open a Developer PowerShell for Visual Studio first so cl.exe can be found. Then, from the repository root:

cmake --preset msvc-release
cmake --build out/build/msvc-release

clang-release, clang-debug and msvc-debug work too.

Antivirus warnings

The loaders get into a game's process and hook functions there. That's just what mod loaders do, but some antivirus software flags it anyway. A warning on its own doesn't mean a release is malicious.

To stay safe, only download releases from this repository and check the SHA-256 digest published with each one. The binaries are self-signed so you can tell if they were tampered with, but Windows won't trust that certificate by default, and it isn't meant as a seal of approval. Please don't turn off your antivirus to run URKit. If you hit a false positive, report it to the antivirus vendor or open an issue here, and include the detection name, the file and its SHA-256 digest.

License

URKit is available under the MIT License.