What it does
Wasmtime is a standalone runtime for WebAssembly, WASI, and the Component Model. Developers can run a compiled `.wasm` module with its command-line tool or embed Wasmtime as a library in a host application. The project is part of the Bytecode Alliance and uses the Apache License 2.0.
Bring a compiled module
Wasmtime runs WebAssembly modules; it is not the compiler that turns a project's source code into a .wasm file. For a first check, the CLI documentation shows wasmtime module.wasm as the basic run pattern. A developer can use the CLI to test a module on its own, or use the embedding API when another program needs to instantiate and manage WebAssembly code. The useful choice is whether the runtime should be a command-line tool or a library inside the host application. The docs cover additional CLI options and APIs, but the module still needs to be built for compatible WebAssembly interfaces and any host capabilities it expects. The official source tree is Apache-2.0 licensed.
Strengths
- The CLI provides a straightforward way to execute a compiled WebAssembly module.
- The same project offers an embedding API for applications that need to manage runtime instances.
- Wasmtime supports WebAssembly, WASI, and the Component Model.
Watch out for
- The runtime does not replace the language compiler or other tool that produces the module.
- A module must match the runtime interfaces and host capabilities available in its intended environment.
Best for
- Developers testing WebAssembly modules outside a browser.
- Application teams embedding a WebAssembly runtime behind a host API.
Sources
- Wasmtime (Oct 25, 2026)
- Using the Wasmtime CLI - Wasmtime (Oct 25, 2026)
- LICENSE | bytecodealliance/wasmtime (Oct 25, 2026)