● Covered by 1 source · 1 reportMedium impact1 neutral
NetWasm Compiler Produces Smaller WebAssembly Binaries for C# Than Rust
Key points
- NetWasm compiles C# directly to WebAssembly without desktop CLR or Mono.
- NetWasm produces 47,895-byte WASI components for a 'print-42' workload.
- Rust's equivalent output is 53,635 bytes, making NetWasm 10.7% smaller.
- NetWasm includes a precise garbage collector and runtime in its size.
NetWasm Achieves Smaller WASM Output
NetWasm, an independent compiler and runtime for .NET, now generates smaller WebAssembly (WASM) binaries for C# applications compared to Rust. For a specific 'print-42' workload, NetWasm produces a 47,895-byte WASI Preview 2 component. This figure includes its runtime and a precise Compact garbage collector.
In comparison, Rust 1.95.0, using a size-oriented profile, generates a 53,635-byte component for the same workload. This makes NetWasm's output 10.7% smaller in raw size and 19.5% smaller when compressed with Brotli-11.
Compiler and Build Process Details
NetWasm is an independent compiler, CoreLib, runtime, and SDK that directly compiles C# and .NET CIL to WebAssembly. It does not include the desktop CLR, Mono, dotnet.js, or application DLLs in production builds. The reported size for NetWasm is from its default Release publish of a template application.
Rust's comparison figure uses Cargo's documented size settings, including opt-level = "z", LTO, one codegen unit, panic = "abort", and stripped symbols. Binaryen's wasm-opt is integrated into NetWasm's compiler pipeline, running in every ordinary build without additional installation or enabling. For Rust's wasm32-wasip2 output, applying wasm-opt requires manual extraction, optimization, and re-encoding of the component.
Performance Benchmarks
Beyond size, NetWasm also demonstrates faster allocation and garbage-collection benchmarks compared to Mono AOT. These tests were conducted on an Apple M1 Max using Wasmtime 49.0.3, with results verified against desktop .NET. NetWasmGC also showed lower execution times than desktop .NET 11's JIT for two out of three workloads.
Implications for WebAssembly Development
This development provides C# developers with a more efficient option for deploying applications to WebAssembly and WASI environments, particularly where binary size is a critical factor. While both C# and Rust can achieve even smaller sizes by foregoing standard libraries or garbage collectors, NetWasm's current results represent out-of-the-box build configurations.
✨ This summary was generated by AI from the outlets' reporting listed below. It is not independently verified and may contain errors — check the original sources. How BrevFeed works →
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Primary sources
GitHub cmc_internal/api GitHub github/collect GitHub zion-sati/NetWasm GitHub _private/browser GitHub get-started/accessibility GitHub open-source/sponsorsReporting from
NetWasm, an independent compiler for .NET, now generates WebAssembly binaries that are smaller than those produced by Rust for a comparable workload. For a 'print-42' workload, NetWasm's output is 47,895 bytes compared to Rust's 53,635 bytes, including a precise garbage collector and runtime. This development offers C# developers a more compact deployment option for WebAssembly and WASI applications.