zion-sati/NetWasm

What is it?

Key features

• 01Compiles C# and .NET CIL directly to standalone WASI Preview 2 components.
• 02Links only reachable code and needed runtime support to keep binaries small.
• 03Offers Compact, NetWasmGC and Bump garbage collector strategies.
• 04Publishes C# exports as typed JavaScript modules, including Web Worker use.
• 05Generates C# bindings from WIT and supports static .a native interop.
• 06Builds and tests through the standard dotnet CLI.

Use cases

• Shipping small C# functions to a WebAssembly host or serverless runtime.
• Running C# logic inside a browser page or Web Worker as a typed JavaScript module.
• Building portable C# libraries that target both NetWasm and desktop .NET.
• Evaluating C# as a compact Wasm alternative to larger Blazor WebAssembly builds.

Quick start

1. 1

   Install the .NET SDK 10.0.303 or newer

2. 2

   Install the NetWasm project templates

   dotnet new install NetWasm.Templates
3. 3

   Create a new NetWasm app and run it

   dotnet new netwasm-app -n HelloNetWasm
4. 4

   Publish the app as a standalone WASI component

   dotnet publish -c Release -o publish/local

Things to know

• !NetWasm is pre-1.0, so source, package and ABI contracts may change between minor releases.
• !Runtime reflection, dynamic, runtime assembly loading and managed threading are not supported.
• !General file, directory, socket and subprocess APIs are not yet implemented.
• !The published component needs a WebAssembly host such as Wasmtime to run.

Topics

FAQ

What is NetWasm?

A C# and .NET CIL to WebAssembly compiler with its own CoreLib, runtime and SDK, producing small standalone WASI Preview 2 components. NetWasm compiles C# and .NET CIL directly to WebAssembly, using its own compiler, CoreLib, runtime and SDK rather than shipping the desktop CLR, Mono or application DLLs. The compiler works from the reachable program and links only the runtime support it needs, so the output is a self-contained WASI Preview 2 component that is run by a Wasm host such as Wasmtime, while the build itself uses the ordinary dotnet CLI.

Is NetWasm free to use? What license does it have?

NetWasm is open source under the Other license. Check the license terms before using it in commercial products.

Is NetWasm still maintained?

Actively maintained. The last commit to NetWasm was on Oct 22, 2026.

What can I use NetWasm for?

Shipping small C# functions to a WebAssembly host or serverless runtime. Running C# logic inside a browser page or Web Worker as a typed JavaScript module. Building portable C# libraries that target both NetWasm and desktop .NET. Evaluating C# as a compact Wasm alternative to larger Blazor WebAssembly builds.

How do I install NetWasm?

Install the .NET SDK 10.0.303 or newer Install the NetWasm project templates: dotnet new install NetWasm.Templates Create a new NetWasm app and run it: dotnet new netwasm-app -n HelloNetWasm Publish the app as a standalone WASI component: dotnet publish -c Release -o publish/local

Where can I get NetWasm?

The source code and installation instructions are on GitHub: https://github.com/zion-sati/NetWasm