Open-source alternatives to Wasm Micro Runtime

rusty_v8 is a Rust wrapper for the V8 JavaScript engine that allows for the embedding of a JavaScript runtime into native applications. It provides core components for managing engine bindings, memory allocation, sandboxed isolates, and the execution of WebAssembly modules. The project features a native host function bridge to map Rust functions to JavaScript objects and a dedicated memory allocator to manage thread-safe allocation and heap pressure. It includes a system for compiling and executing binary WebAssembly modules within the hosted native environment. The runtime covers capabiliti

Wasmtime is a WebAssembly runtime and sandboxed bytecode executor designed to run WebAssembly bytecode on a host system. It functions as an embeddable engine that integrates into applications through native APIs and language-specific bindings, as well as a standalone execution environment accessible via a command line interface. It is a WASI compatible runtime, implementing the WebAssembly System Interface to provide portable access to system resources. The engine utilizes a JIT compilation model to translate intermediate representation into optimized machine code for various CPU architecture

AssemblyScript is a compiler and tooling suite used for WebAssembly module development. It converts a subset of TypeScript syntax into binary modules to achieve high execution speeds and cross-platform binary execution. The project focuses on translating typed source code into the compact binary format required by WebAssembly runtimes. This allows for the movement of computationally heavy logic into binary modules for browser performance optimization and execution across different operating systems. The compilation process involves TypeScript-compatible syntax analysis and the generation of

TinyGo is a specialized compiler and development toolkit designed to bring the Go programming language to resource-constrained microcontrollers and WebAssembly environments. It provides a bare-metal runtime environment that enables high-level code execution without the need for a traditional operating system, utilizing an LLVM-based backend to generate efficient machine instructions. The project distinguishes itself through aggressive optimization techniques tailored for small hardware, including a static memory allocation strategy and whole-program dead code elimination that significantly re

Extism is a cross-language WebAssembly plugin framework that lets applications written in any programming language load and execute plugins written in any other language. It provides a universal plugin system where host applications use idiomatic SDKs to load WebAssembly modules, call exported functions, and pass data back and forth, while plugin authors use development kits that handle memory management and host interaction so they can focus on business logic. The framework distinguishes itself through its comprehensive approach to cross-language integration, offering schema-driven binding g

V8 is a high-performance JavaScript and WebAssembly engine designed to compile and execute code within host applications. It functions as an embeddable scripting engine and just-in-time compiler, providing a portable library for integrating dynamic script execution into native software environments. The engine incorporates a WebAssembly runtime to execute compiled binary code for a stack-based virtual machine at near-native speeds. It enables native application scripting by allowing a JavaScript execution environment to be embedded directly into a native program to handle dynamic logic. The

Wasm3 is a WebAssembly interpreter designed for embedded runtime integration. It enables the execution of portable binary logic on microcontrollers and resource-constrained hardware, providing support for modules that utilize the WebAssembly System Interface to interact with system resources. The runtime employs register-based bytecode interpretation and direct-threaded dispatch to map virtual registers to physical CPU registers. It includes a host-call interface to map imports to C functions and utilizes static module validation to ensure bytecode follows specification rules before execution

This project provides a full Python interpreter compiled to WebAssembly, enabling the execution of Python code and scientific libraries directly within web browsers and server-side environments. By bridging the gap between language runtimes, it allows developers to run computational tasks, manage packages, and perform data analysis in client-side environments without requiring a backend server. The platform distinguishes itself through a comprehensive foreign function interface that enables bidirectional data exchange, object proxying, and function calling between Python and JavaScript. It in

JupyterLite is a WebAssembly-based interactive notebook environment that enables browser-based computing without a backend server. It provides a client-side data science sandbox where users can execute programming language kernels and run interactive notebooks entirely within the web browser. The project allows for the creation of tailored distributions by pre-installing specific language packages, bundling custom wheels, and applying environment configurations. It supports the generation of static sites that can be deployed to any standard HTTP host, including the ability to package the envi

Wasmer is a high-performance runtime engine designed to execute sandboxed WebAssembly modules across server-side, edge, and browser environments. It functions as a comprehensive platform for building, distributing, and running isolated applications, providing a secure and portable execution layer that maintains consistency across diverse hardware architectures and operating systems. The platform distinguishes itself through a robust toolchain that enables cross-language interoperability and the transformation of code into portable binary packages. It supports ahead-of-time binary generation t

Linera is a multi-chain smart contract platform designed for horizontal scalability through a microchain-based distributed ledger. By partitioning state into independent, parallel chains that share a common validator set, the protocol enables high-performance execution of modular applications. The system utilizes a WebAssembly-based runtime to ensure secure, platform-independent execution of contract logic across the network. The platform distinguishes itself through an asynchronous messaging framework that coordinates state changes between chains by queuing messages for execution in subseque

esbuild is a high-performance JavaScript bundler and transpiler designed to transform modern web assets into production-ready code. Built with a focus on speed, it utilizes a concurrent execution model to perform parsing, linking, and code generation across multiple CPU cores. The engine handles a wide range of tasks, including TypeScript compilation, JSX transformation, and CSS bundling, while maintaining a consistent build process across diverse environments. What distinguishes the project is its architecture, which leverages memory-mapped file processing and a single-pass transformation st

Emscripten is a WebAssembly toolchain and compiler backend that transforms C and C++ source code into WebAssembly bytecode. It serves as a framework for porting native applications and libraries to web browsers and server runtimes by translating LLVM intermediate representation into optimized WebAssembly modules. The system specializes in porting native graphical standards, such as OpenGL and SDL2, by mapping native graphics API calls to browser-compatible WebGL commands. This allows complex visual applications and native desktop software to be deployed as portable web formats. The toolchain

This project is a suite of basic command line utilities rewritten in Rust, providing a cross-platform implementation of POSIX shell utilities. It serves as a portable CLI toolset designed to run across different operating systems and architectures. The implementation includes a WebAssembly shell environment, which allows these essential command line tools to be executed directly within a web browser without requiring a local installation. The toolset covers a broad range of system capabilities, including filesystem operations, text processing and stream editing, and system administration too

Datasette is a tool for publishing and sharing SQLite databases as public websites. It functions as a data publishing system that provides searchable interfaces and JSON APIs to expose the contents of SQLite files. The project enables both server-side and client-side execution. It can operate as an API server or as a database browser that runs entirely within a web browser using WebAssembly, allowing for serverless database access. The system supports a variety of deployment strategies, including containerized images for cloud hosting and a local development server for testing. It includes c

Scala Native is an ahead-of-time compiler that transforms Scala source code into standalone native binaries for direct execution on hardware. It provides a native binary toolchain designed to eliminate virtual machine warm-up times and ensure instant startup by compiling code into optimized executables. The project features a C interoperability interface and foreign function interface that map native C headers to language objects, allowing for the direct execution of external libraries. It includes a low-level memory manager that supports direct pointer manipulation and the use of structs for

Preswald is a WebAssembly data application framework used to build interactive data apps that run entirely in the browser using Python. It provides a browser-based data stack, including SQL and Python execution, that operates offline without the need for a backend server. The framework includes a static data app bundler to package data workflows and visualizations into single, shareable files. These self-contained applications enable serverless data visualization and portable data workflow bundling for distribution. The system utilizes a reactive data dashboard interface that updates specifi

Substrate is a modular blockchain development framework used to build customized blockchain networks with programmable state transitions and consensus mechanisms. It functions as a toolkit for constructing bespoke network protocols and deploying nodes to local environments or global testnets. The framework utilizes a WebAssembly runtime environment to execute state transition logic, ensuring deterministic behavior across all network nodes. It enables the composition of modular logic components and runtime palettes to define the specific rules and behavior of a blockchain. The system covers c

This repository contains the design specifications for WebAssembly, serving as a technical standard for portable low-level code. It defines the binary format, instruction set, and execution semantics required to ensure consistent behavior across different hardware platforms. The project establishes the framework for a language compilation target, detailing the requirements for translating high-level programming languages into a low-level binary format. It includes a security model that defines operational rules and safety goals for executing untrusted binary code. The specifications cover th

Binaryen is a WebAssembly compiler toolchain and optimizer designed to transform, validate, and shrink binary modules. It provides a comprehensive intermediate representation framework that converts binary code into a single-assignment form to enable advanced program analysis and code transformation. The project includes a specialized transformation engine that applies iterative optimization passes to increase execution speed and reduce binary size. Additionally, it functions as a transpiler that translates WebAssembly binary modules into executable JavaScript for environments that lack nativ

Lunatic is a WebAssembly runtime and concurrent process manager that implements an Erlang-inspired model of lightweight concurrency and fault tolerance. It functions as a distributed actor system where isolated processes communicate via message passing across a network of linked nodes. The system utilizes a WebAssembly sandbox environment to isolate memory and restrict system call permissions for each individual process. This capability-based security model ensures that processes are sandboxed to safely execute untrusted code. The platform provides a fault-tolerant supervision tree for hiera

This project is a Go WebAssembly frontend framework designed for building interactive web applications. It provides a toolkit for executing Go code directly in the browser to handle client-side logic and user interface development. The framework functions as a declarative UI library and a progressive web app toolset. It enables the creation of installable applications that can operate in standalone windows and maintain offline functionality. The system manages browser-side application development through a component-based view hierarchy and a declarative syntax for defining UI elements. It i

Mago is a PHP static analysis tool, linter, and code formatter. It detects type errors, dead code, and logic bugs through advanced type inference and flow analysis, while providing a deterministic engine to rewrite source files according to style guides. The project distinguishes itself with a WebAssembly runtime that enables PHP analysis to execute entirely within a web browser, allowing results to be shared via URL. It also provides a minimal Dockerized toolchain distributed as a scratch image for consistent execution across different processor architectures. The toolset covers architectur

GraalVM is a polyglot virtual machine and high-performance runtime designed to execute multiple programming languages within a single environment. It functions as a JVM language toolkit for building language implementations, a native image compiler for transforming bytecode into standalone binaries, and an execution environment for LLVM bitcode and WebAssembly modules. The project is distinguished by its polyglot interoperability framework, which allows different languages to share data and execution state with low overhead. It utilizes self-modifying abstract syntax trees to optimize languag

Youki is a low-level container runtime written in Rust that creates and manages isolated containers according to Open Container Initiative specifications. It serves as an execution engine that can function as a rootless container manager or a pluggable Kubernetes CRI runtime to manage pods and containers within a cluster. The project distinguishes itself by providing a Wasm container runtime capable of executing WebAssembly modules as isolated workloads compatible with standard orchestration tools. It further supports a rootless execution model, allowing isolated environments to start as non-

Squoosh is a browser-based image optimizer that compresses and converts image files directly within the local environment. By performing all operations on the user device, it eliminates the need for server-side processing, ensuring that sensitive data remains private and reducing network latency. The tool utilizes a collection of high-performance image codecs compiled via WebAssembly to provide professional-grade file optimization and format conversion. To maintain interface responsiveness during resource-intensive tasks, the application offloads image manipulation to background threads and u

Pglite is a client-side relational database engine that runs a full-featured PostgreSQL instance directly within browser and Node.js environments. By leveraging WebAssembly, it provides a persistent SQL storage solution that enables complex data management and querying without requiring an external database server. The project distinguishes itself through a reactive SQL data layer that automatically synchronizes user interface components with live query results. It manages database operations using worker threads to prevent main-thread blocking and coordinates access across multiple browser t