Wasmer

Wasmer is an open-source WebAssembly runtime designed to execute WebAssembly modules outside the web browser. It aims to provide a portable, secure, and high-performance environment for running Wasm code on servers, desktops, edge devices, and embedded systems. By enabling Wasm to run outside the browser, Wasmer supports use cases such as serverless functions, plugin systems, and sandboxed execution of third-party code.

The project offers an embeddable runtime with a layered architecture. Wasmer Core provides the stable interface for loading, compiling, and executing modules, while engines manage the actual compilation and execution. Wasmer supports multiple compilation backends, including Cranelift, LLVM, and Singlepass, allowing users to choose a balance between startup time and runtime performance. A command-line tool (the Wasmer CLI) and language bindings enable running Wasm modules from various ecosystems, and WASI (WebAssembly System Interface) support allows Wasm modules to interact with the host environment through a controlled interface.

Key features include ahead-of-time and just-in-time compilation, caching of compiled artifacts to speed up subsequent runs, and sandboxed execution consistent with WebAssembly’s isolation guarantees. Wasmer provides host function imports and bindings for several programming languages, enabling embedding in languages such as Rust, Go, Python, and JavaScript, among others, via a C API and respective language SDKs.

Typical use cases encompass server-side applications, edge computing workloads, and platforms that require safe, isolated execution of third-party Wasm modules. Wasmer is developed and maintained by Wasmer Inc., together with contributions from the open-source community, and is distributed as an open-source project with ongoing development and ecosystem growth.