osu-framework is an MIT-licensed C# game framework from the osu! team for developers who want the UI, text rendering, input handling and testing scaffolding of a shipped rhythm game as the starting point for their own project.

What it is

osu-framework is a game framework written in C# for the .NET ecosystem, and its own description is simply "a game framework written with osu! in mind." It is listed under Miscellaneous / Gaming, and its stated objective is to go beyond what is normally expected of a game framework: basic UI elements, text rendering, advanced input handling including textboxes, and performance overlays are provided out of the box. Any osu! code that is deemed useful to other game projects lives in this framework rather than staying inside the game.

The problem it solves is the foundation work that precedes an actual game. Graphical components are implemented with a generic design and are derivable for further customisation, while common elements such as texture caching and font loading are initialised automatically at runtime, so a team does not have to rebuild that layer for each project. The framework targets the .NET 10 SDK, and on Linux it expects a system-wide ffmpeg installation to support video decoding.

Key capabilities

• Project templates in osu.Framework.Templates supply a full project structure, cross-platform support and a testing setup, starting from either an empty project or a working sample game.
• Basic UI elements, text rendering, advanced input handling such as textboxes, and performance overlays are available out of the box.
• Components can be developed in isolation through the VisualTests project and TestCases, which the README recommends for new component work.
• Common elements including texture caching and font loading are initialised automatically at runtime.
• Building uses the supplied platform-specific .slnf files rather than the main .sln, which keeps the template run configurations available in Visual Studio and Rider.
• Code analysis can be run with powershell ./InspectCode.ps1 or InspectCode.sh.

Who uses it and how

• C# game teams on desktop platforms use it as the base layer for a new title, adopting the project templates instead of starting from an empty repository.
• It is the designated home for osu! code that is useful to other game projects, so work done for the game lands in a library that other titles can consume.
• Component contributors are directed to work inside VisualTests and TestCases, keeping component development isolated from a full game build; the repository's hacktoberfest topic and "good first issue" label point open-source contributors at entry points among its 467 open issues.
• Linux developers can run the same codebase provided ffmpeg is installed system-wide, and IDE users load the platform-specific .slnf so the template run configurations are present.

Getting started

The wiki's "Setting up your first project" page is the documented entry point, and osu.Framework.Templates provides the starting point as either an empty project or a working sample game with project structure, cross-platform support and a testing setup already included. Building is then done through the IDE's own build and run functionality after loading the matching platform-specific .slnf file.

How it compares

No list of paid products that osu-framework replaces is given, and no comparable tool is named in its materials, so it stands alone in this registry. Its only stated contrast is with the ordinary expectations of a game framework, which the authors deliberately set out to exceed by shipping UI, text rendering, input and performance overlays rather than leaving them to the developer.

When to use it — and when not to

Reach for it when the project is a C# game on .NET 10 targeting desktop platforms and the team wants the reusable layer of a shipped game, covering UI, text rendering, input, overlays and a testing harness, under the MIT licence. Adopting teams must operate a .NET 10 SDK toolchain, pick the correct platform-specific .slnf for builds, and install ffmpeg system-wide on Linux for video decoding. Teams outside .NET should not pick it, and neither should anyone expecting user-facing documentation in the repository: the README states that its content covers working on the framework rather than using it, and 467 open issues against 2,031 stars indicate a busy maintenance queue.