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Wasmer Runtime

Wasmer Runtime

The Wasmer Runtime runs WebAssembly modules and packages from the Wasmer Registry in lightweight, capability-based sandboxes. Use it as a command-line tool or embed it directly in a JavaScript or Python application.

InterfaceBest forInstall
Wasmer CLIRunning packages from a terminal or scriptcurl https://get.wasmer.io -sSfL | sh
JavaScript SDKNode.js and browser applicationsnpm install @wasmer/sdk
Python SDKPython applications and AI agentspython -m pip install wasmer-sdk

All three interfaces use the same Wasmer packages and WASIX runtime. The SDKs also expose a shared sandbox model for composing packages, files, environment variables, networking, and long-running processes inside a host application.

First steps

Start with one package, then choose the interface that fits your host application.

Features

  • Secure by default. No file, network, or environment access, unless explicitly enabled.
  • Fast. Run WebAssembly at near-native speeds.
  • Embeddable. Run sandboxes in JavaScript, Python, Rust, and other host applications without a separate daemon.
  • Compliant with the latest WebAssembly proposals (SIMD, Reference Types, Threads, …)

Backends

The Wasmer Runtime supports multiple backends, depending on your needs:

Wasmer backends

  • Singlepass: A single-pass compiler for fast compilation times and low memory usage.
  • Cranelift: A fast compiler backend with a focus on compile times, and runtime performance.
  • LLVM: A compiler backend that uses LLVM for optimization and code generation.

Integration backends

  • Browser: it allows running Wasmer fully in the browser (via wasm-bindgen).
  • V8: it allows running Wasmer using the WebAssembly engine inside V8 (can run in interpreter mode or with JIT)
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