Awesome Open Source
Awesome Open Source


WAPM GitHub issues Tests status Fuzzing Status GitHub license

The fastest WebAssembly interpreter, and the most universal runtime.
Based on CoreMark 1.0 and independent benchmarks. Your mileage may vary.

Twitter Discord Telegram

Getting Started

Here's a small getting started guide. Click here to start:



Please follow the installation instructions.

Wasm3 can also be used as a library for:

Arduino, PlatformIO, Particle QuickJS


wasm3 passes the WebAssembly spec testsuite and is able to run many WASI apps.

Minimum useful system requirements: ~64Kb for code and ~10Kb RAM

wasm3 runs on a wide range of architectures (x86, x86_64, ARM, RISC-V, PowerPC, MIPS, Xtensa, ARC32, ...) and platforms:

  • Linux, Windows, OS X, FreeBSD, Android, iOS
  • OpenWrt, Yocto, Buildroot (routers, modems, etc.)
  • Raspberry Pi, Orange Pi and other SBCs
  • MCUs: Arduino, ESP8266, ESP32, Particle, ... see full list
  • Browsers. Yes, using WebAssembly itself!
  • wasm3 can execute wasm3 (self-hosting)


Webassembly Core Proposals Extra
Import/Export of Mutable Globals Structured execution tracing
Non-trapping float-to-int conversions Big-Endian systems support
Sign-extension operators Wasm and WASI self-hosting
Multi-value Gas metering
Bulk memory operations (partial support) Linear memory limit (< 64KiB)
Multiple memories
Reference types
Tail call optimization
Fixed-width SIMD
Exception handling


Why use a "slow interpreter" versus a "fast JIT"?

In many situations, speed is not the main concern. Runtime executable size, memory usage, startup latency can be improved with the interpreter approach. Portability and security are much easier to achieve and maintain. Additionally, development impedance is much lower. A simple library like Wasm3 is easy to compile and integrate into an existing project. (Wasm3 builds in a just few seconds). Finally, on some platforms (i.e. iOS and WebAssembly itself) you can't generate executable code pages in runtime, so JIT is unavailable.

Why would you want to run WASM on embedded devices?

Wasm3 started as a research project and remains so by many means. Evaluating the engine in different environments is part of the research. Given that we have Lua, JS, Python, Lisp, ... running on MCUs, WebAssembly is actually a promising alternative. It provides toolchain decoupling as well as a completely sandboxed, well-defined, predictable environment. Among practical use cases we can list edge computing, scripting, plugin systems, running IoT rules, smart contracts, etc.

Used by

Further Resources

Installation instructions
Build and Development instructions
Supported Hardware
Testing & Fuzzing
Interpreter Architecture
Awesome WebAssembly Tools


This project is released under The MIT License (MIT)

Get A Weekly Email With Trending Projects For These Topics
No Spam. Unsubscribe easily at any time.
C (275,213
Iot (5,839
Serverless (4,862
Devops (4,029
Containers (3,248
Smart Contracts (2,379
Webassembly (2,302
Embedded (1,898
Wasm (1,760
Virtual Machine (1,078
Scripting (843
Sandbox (566
Edge Computing (331
Cosmopolitan (4
Related Projects