# WAMR — WebAssembly Micro Runtime for Embedded and IoT

> WAMR (WebAssembly Micro Runtime) is a lightweight, high-performance WebAssembly runtime by the Bytecode Alliance. It supports interpreter, ahead-of-time, and JIT compilation modes, targeting resource-constrained devices from MCUs to cloud edge nodes.

## Install

Save in your project root:

# WAMR — WebAssembly Micro Runtime for Embedded and IoT

## Quick Use
```bash
# Build WAMR
git clone https://github.com/bytecodealliance/wasm-micro-runtime.git
cd wasm-micro-runtime/product-mini/platforms/linux
mkdir build && cd build
cmake .. && make

# Run a WASM module
./iwasm test.wasm
```

## Introduction
WAMR is a compact WebAssembly runtime developed under the Bytecode Alliance. It brings the portability and sandboxing of WebAssembly to environments where Wasmtime or V8 would be too large, including microcontrollers, RTOS-based systems, and edge computing platforms.

## What WAMR Does
- Executes WebAssembly modules on devices with as little as 50KB RAM
- Offers three execution modes: interpreter, ahead-of-time (AOT) compilation, and JIT
- Provides WASI (WebAssembly System Interface) support for file and socket access
- Supports multi-threading with the WASM threads proposal
- Embeds into C/C++ host applications via a clean native API

## Architecture Overview
WAMR includes a stack-based interpreter for minimal footprint, an AOT compiler that translates WASM to native code offline, and an optional LLVM-based JIT for runtime compilation. The runtime manages linear memory, tables, and module instances inside a sandboxed execution environment. A built-in app management framework supports dynamic loading and lifecycle control of WASM apps.

## Self-Hosting & Configuration
- Build with CMake; select execution mode via cmake flags (-DWAMR_BUILD_INTERP, -DWAMR_BUILD_AOT)
- Cross-compile for Zephyr, NuttX, RT-Thread, or bare-metal ARM targets
- Use wamrc to ahead-of-time compile WASM to native for production deployment
- Enable WASI for filesystem and network access in supported environments
- Embed in a host app by linking libiwasm and calling wasm_runtime_* APIs

## Key Features
- Runs on devices with as little as 50KB RAM (interpreter mode)
- Three execution modes cover the spectrum from MCU to server
- WASI support for portable system access
- Dynamic module loading and unloading at runtime
- Hardware-sandboxed execution isolates untrusted code

## Comparison with Similar Tools
- **Wasmtime** — full-featured Bytecode Alliance runtime; WAMR targets smaller footprint
- **Wasmer** — developer-friendly with package registry; WAMR focuses on embedded constraints
- **wasm3** — pure interpreter with tiny footprint; WAMR adds AOT and JIT for higher throughput
- **WasmEdge** — cloud-native WASM runtime; WAMR targets deeper embedded use cases

## FAQ
**Q: What is the minimum hardware for WAMR?**
A: The interpreter runs on Cortex-M4 with 50KB RAM. AOT mode needs more flash but runs faster.

**Q: Can I use WAMR in a cloud environment?**
A: Yes. WAMR runs on Linux, macOS, and Windows and is used in edge computing and serverless platforms.

**Q: What languages can I compile to WASM for WAMR?**
A: C, C++, Rust, Go (TinyGo), AssemblyScript, and any language with a WASM compilation target.

**Q: Is WAMR production-ready?**
A: Yes. It is used in production by Intel, Xiaomi, Midea, and other companies for IoT and edge workloads.

## Sources
- https://github.com/bytecodealliance/wasm-micro-runtime
- https://bytecodealliance.org/

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Author: AI Open Source