dotnet/runtimelab

The .NET Runtime Lab is a sandbox where Microsoft and community contributors test experimental ideas for the .NET platform before deciding whether they are good enough to ship to the official .NET runtime. Think of it as a staging ground or R&D workshop: features get prototyped here, tested out, and either graduate into the main product or get shelved. The repo currently hosts over a dozen active experiments. Some aim to improve performance and reach, like bringing .NET to FreeBSD or using LLVM compilation to produce smaller, faster native binaries (including for WebAssembly). Others explore new data types, like a native UTF-8 string that could make text handling more efficient. There are also infrastructure experiments: a fully managed implementation of the QUIC networking protocol, lower-level HTTP APIs, Swift language bindings, and a garbage collector designed purely to measure maximum allocation speed. Anyone can propose and create their own experiment, and several past experiments have already been accepted into the official .NET runtime. The audience is primarily .NET developers and compiler enthusiasts who want early access to upcoming features or who want to contribute to the language's evolution. For example, a developer building apps for niche platforms like FreeBSD or s390x mainframes would find ports here. Someone interested in ahead-of-time compilation for Android or faster JSON processing can experiment with those prototypes. It is also useful for developers who want to understand where .NET is heading and which capabilities might land in future versions. What is notable is the explicit tradeoff: this is experimentation territory, not a stable product. Features may be incomplete, may change significantly, or may never ship at all. The repo keeps each experiment on its own branch, which keeps things isolated but means you need to know which feature you are after. It is a low-friction way for the .NET team to explore ambitious ideas without destabilizing the production runtime.