zwasm

A standalone WebAssembly runtime written in Zig. Runs Wasm modules as a CLI tool or embeds as a Zig library.

Features

Full Wasm 3.0 support: Core spec + 9 proposals (GC, exception handling, tail calls, SIMD, threads, and more)
62,158 spec tests passing: 100% on macOS ARM64 and Linux x86_64
4-tier execution: Interpreter with register IR and ARM64/x86_64 JIT compilation
WASI Preview 1: 46 syscalls with deny-by-default capability model
Small footprint: 1.31 MB binary, 3.44 MB runtime memory
Library and CLI: Use as a zig build dependency or run modules from the command line
WAT support: Run .wat text format files directly

# Run a WebAssembly module
zwasm hello.wasm

# Invoke a specific function
zwasm math.wasm --invoke add 2 3

# Run a WAT text file
zwasm program.wat

See Getting Started for installation instructions.