Wasmrun

Wasmrun is a powerful WebAssembly runtime that simplifies development, compilation, and deployment of WebAssembly applications.

✨ Features

• 🚀 Multi-Language Support - Build WebAssembly from Rust, Go, Python, C/C++, and AssemblyScript
• 🔌 Plugin Architecture - Extensible system with built-in and external plugins
• 🔥 Live Reload - Instant development feedback with file watching
• 🌐 Zero-Config Web Server - Built-in HTTP server with WASM and web app hosting
• 📦 Smart Project Detection - Automatically detects and configures project types
• ⚡ Zero Configuration - Works out of the box with sensible defaults and automatic project detection

🚀 Installation

From Cargo (Recommended)

cargo install wasmrun

From Prebuilt Packages

Wasmrun is available as a DEB package for Debian-based systems.

1. Download the latest .deb file from GitHub Releases
2. Install the package:

# Install the downloaded DEB package
sudo apt install wasmrun_*.deb

# If there are dependency issues, fix them
sudo apt install -f

Wasmrun is available as an RPM package for Red Hat-based systems.

1. Download the latest .rpm file from GitHub Releases
2. Install the package:

# Install the downloaded RPM package
sudo rpm -i wasmrun-*.rpm

# Or using dnf (Fedora/RHEL 8+)
sudo dnf install wasmrun-*.rpm

Track releases on github releases or via release feed.

From Source

git clone https://github.com/anistark/wasmrun.git
cd wasmrun
cargo install --path .

📖 Usage

Wasmrun supports both flag-based arguments using --path and direct positional arguments for an intuitive command line experience.

Quick Start

# Run on current directory
wasmrun

# Run a WebAssembly file directly  
wasmrun myfile.wasm

# Run a project directory
wasmrun ./my-wasm-project

# With flags
wasmrun --path ./path/to/your/file.wasm
wasmrun --path ./my-wasm-project

🔧 Commands

Development Server

Start the development server with live reload:

wasmrun run ./my-project --watch
wasmrun run ./my-project --port 3000 --language rust

Compilation

Compile a project to WebAssembly using the appropriate plugin:

wasmrun compile ./my-project
wasmrun compile ./my-project --output ./build --optimization release
wasmrun compile ./my-project --optimization size --verbose

Plugin Management

List available plugins and manage external plugins:

# List all available plugins
wasmrun plugin list

# Install external plugins
wasmrun plugin install wasmrust
wasmrun plugin install wasmgo

# Get detailed plugin information
wasmrun plugin info wasmrust
wasmrun plugin info wasmgo

Verification & Inspection

Verify a WASM file format and analyze structure:

wasmrun verify ./file.wasm
wasmrun verify ./file.wasm --detailed

wasmrun inspect ./file.wasm

Project Management

Initialize a new project:

wasmrun init my-app --template rust
wasmrun init my-app --template go --directory ./projects/

Clean build artifacts:

wasmrun clean ./my-project

Server Control

Stop any running Wasmrun server:

wasmrun stop

🏗️ Plugin Architecture

Wasmrun's modular plugin architecture enables seamless integration of different programming languages and compilation toolchains into a unified development experience. Here's a detailed guide on wasmrun plugin architecture.

Plugin Types

1. Built-in Plugins 🔧

Built-in plugins are compiled directly into Wasmrun and provide core language support:

Plugin	Language	Compiler	Status	Capabilities
C/C++	C, C++	Emscripten	✅ Stable	Full WASM + Web Apps + Makefiles

2. External Plugins 📦

External plugins are distributed via crates.io and installed dynamically to ~/.wasmrun/:

Plugin	Language	Compiler	Installation	Capabilities
wasmasc	AssemblyScript	asc	wasmrun plugin install wasmasc	WASM + Optimization + npm/yarn/pnpm/bun
wasmrust	Rust	rustc + wasm-pack	wasmrun plugin install wasmrust	Full WASM + Web Apps + Optimization
wasmgo	Go	TinyGo	wasmrun plugin install wasmgo	WASM + Optimization + Package Support
waspy	Python	waspy	wasmrun plugin install waspy	WASM + Python-to-WASM Compilation

How External Plugins Work:

• 📦 Cargo-like Installation: Similar to cargo install, plugins are downloaded and compiled to ~/.wasmrun/
• 🔗 Dynamic Loading: Plugins are loaded as shared libraries (FFI) at runtime
• 🎯 Same Interface: External plugins use identical traits as built-in plugins
• 🔧 Auto-detection: Once installed, plugins automatically handle their supported project types

Plugin Management

# Install external plugins
wasmrun plugin install wasmrust # Rust plugin
wasmrun plugin install wasmgo   # Go plugin
wasmrun plugin install waspy    # Python plugin
wasmrun plugin install wasmasc  # AssemblyScript plugin

# View all installed plugins
wasmrun plugin list

# Get detailed plugin information
wasmrun plugin info <plugin-name>

# Uninstall plugins
wasmrun plugin uninstall <plugin-name>

Plugin Installation Process:

1. 🔍 Discovery: Searches crates.io for the plugin
2. 📦 Download: Uses cargo install to build the plugin
3. 🏠 Storage: Installs to ~/.wasmrun/plugins/{plugin_name}/
4. 📋 Registration: Updates wasmrun config with plugin capabilities
5. ⚡ Ready: Plugin automatically handles supported projects

🛠️ Language Support

Rust (via External Plugin)

# Install the Rust plugin
wasmrun plugin install wasmrust

# Run Rust projects
wasmrun ./my-rust-wasm-project

Requirements:

• Rust toolchain
• wasm32-unknown-unknown target: rustup target add wasm32-unknown-unknown
• Optional: wasm-pack for web applications

Go (via External Plugin)

# Install the Go plugin
wasmrun plugin install wasmgo

# Run Go projects
wasmrun ./my-go-wasm-project

Requirements:

• TinyGo compiler: https://tinygo.org/

Python (via External Plugin)

# Install the Python plugin
wasmrun plugin install waspy

# Run Python projects
wasmrun ./my-python-wasm-project

Requirements:

• None! waspy is a pure Rust compiler that compiles Python to WebAssembly

Features:

• ✅ Python to WebAssembly compilation
• ✅ Support for functions, classes, and basic Python syntax
• ✅ Type annotations support
• ✅ No Python runtime required

AssemblyScript (via External Plugin)

# Install the AssemblyScript plugin
wasmrun plugin install wasmasc

# Run AssemblyScript projects
wasmrun ./my-assemblyscript-project

Requirements:

• AssemblyScript compiler: npm install -g asc
• Node.js runtime

Package Manager Support: The plugin automatically detects and uses your preferred package manager:

• npm (default)
• yarn (via yarn.lock)
• pnpm (via pnpm-lock.yaml)
• bun (via bun.lockb)

C/C++ (Built-in)

# Works out of the box - no plugin installation needed
wasmrun ./my-c-project

Requirements:

• Emscripten SDK: https://emscripten.org/

🔍 Project Detection

Wasmrun automatically detects your project type based on:

• File extensions (.rs, .go, .py, .c, .cpp, .ts)
• Configuration files (Cargo.toml, go.mod, Makefile, package.json)
• Entry point files (main.rs, main.go, main.py, main.c, etc.)

You can override detection with the --language flag:

wasmrun --language rust ./my-project
wasmrun --language go ./my-project
wasmrun --language python ./my-project
wasmrun --language asc ./my-project

🚨 Troubleshooting

Plugin Issues

"Plugin not available"

# For built-in language support:
wasmrun --language c        # C/C++ (built-in)

# For external plugins, install them first:
wasmrun plugin install wasmrust   # Rust plugin
wasmrun plugin install wasmgo     # Go plugin
wasmrun plugin install waspy      # Python plugin
wasmrun plugin install wasmasc    # AssemblyScript plugin

# View all available plugins:
wasmrun plugin list

🚨 Open an issue and let us know about it.

"Plugin dependencies missing"

# Install missing tools for external plugins:
rustup target add wasm32-unknown-unknown  # For wasmrust plugin
go install tinygo.org/x/tinygo@latest     # For wasmgo plugin

# Check plugin dependencies:
wasmrun plugin info wasmrust  # Shows required dependencies
wasmrun plugin info waspy     # Should show no dependencies

"Wrong plugin selected"

# Force a specific plugin
wasmrun --language rust
wasmrun --language go
wasmrun --language python

External Plugin Installation

"Plugin not found during installation"

# Make sure you have the correct plugin name
wasmrun plugin install wasmrust   # For Rust support
wasmrun plugin install wasmgo     # For Go support
wasmrun plugin install waspy      # For Python support

# Check available external plugins
wasmrun plugin list --external

Common Issues

"Port is already in use"

wasmrun stop         # Stop existing server
wasmrun --port 3001  # Use different port

"No entry point found"

• Ensure your WASM has main(), _start(), or exported functions
• Use wasmrun inspect to see available exports
• Check plugin-specific entry file requirements

"wasm-bindgen module detected"

• Use the .js file instead of the .wasm file directly (wasmrust plugin)
• Run wasmrun project-dir instead of individual files

📼 Talks/Demos

A list of wasmrun related talks (latest first): ✨

When	What	Where	Who
Oct 18, 2025	Bringing Python to WebAssembly	PyCon Thailand 2025, Bangkok	Farhaan, Ani
Sept 20, 2025	Your Next Server Might Be a Browser	IndiaFOSS 2025, Bengaluru	Ani
Sept 13, 2025	Compiling Python to WASM	PyCon India 2025, Bengaluru	Farhaan, Ani
July 16, 2025	WASM and Python: The Future of Serverless Computing	EuroPython 2025, Prague, Czech	Farhaan, Ani
May 24, 2025	WASM and Python	BangPypers Meetup	Farhaan, Ani

If you've talked about wasmrun at a conference, podcast, virtual or local meetup, feel free to add to this list 🙌

🤝 Contributing

We welcome contributions! Please see CONTRIBUTING.md for detailed guidelines, including how to create and maintain plugins.

📄 License

MIT License

🙏 Credits

Wasmrun is built with love using:

• tiny_http - Lightweight HTTP server
• clap - Command line argument parsing
• notify - File system watching for live reload
• wasm-bindgen - Web integration
• Font used for logo is Pixeled by OmegaPC777.
• And the amazing Rust and WebAssembly communities ❤️

Made with ❤️ for the WebAssembly community

⭐ If you find Wasmrun useful, please consider starring the repository!