GoKawiilNetWasm compiler claims smaller WASI binaries than Rust and faster runtime than Mono AOT
NetWasm, an independent compiler toolchain that compiles C# and .NET CIL directly to WebAssembly without the desktop CLR or Mono, reports that version 0.8.0 produced a 47,798-byte standalone WASI Preview 2 component for a test workload, versus 53,635 bytes for a size-optimized Rust 1.95.0 build of the same task. Separately, NetWasm 0.10.0 reportedly ran allocation and garbage-collection benchmarks 26-40% faster than Mono AOT on .NET 10, using identical C# source run under the same Wasmtime engine on an Apple M1 Max.
GoKawiil's interpretation of the reporting above, not reported fact.
These are vendor-reported benchmarks on specific workloads rather than broad language comparisons, so the results should be read as evidence of a competitive niche use case rather than proof that C# generally outperforms Rust or Mono on WebAssembly. If independently verified, a smaller and faster .NET-to-Wasm path could make C# more attractive for size- and performance-sensitive edge or WASI deployments where it previously lagged behind Rust and other ahead-of-time compiled languages.
- NetWasm 0.8.0 produced a WASI component 10.9% smaller than a size-optimized Rust 1.95.0 build for the same workload.
- NetWasm 0.10.0 ran GC and allocation benchmarks 26-40% faster than Mono AOT on .NET 10 under identical conditions.
- Comparisons with Kotlin/Wasm and TinyGo show differing runtime boundaries, so results are workload-specific, not a general language ranking.
Source: github.com, 2026-10-21
Published there as: “C# now beats Rust on WASM size”
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