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Wasm Workers Server can run .wasm modules natively. When you run wws in a folder, any file with this extension will run as a worker:


⚙️ Loading routes from: .
🗺 Detected routes:
=> index.wasm (name: default)
🚀 Start serving requests at

However, these are not the only files wws can manage. You can extend wws with different language runtimes to run files from several languages like JavaScript, Ruby and Python.

How are multiple language runtimes supported?

By default, wws only supports Wasm modules and JavaScript files. For any other language, you need the language interpreter or runtime. These runtimes are also Wasm modules. When you run wws, it loads the available runtimes and mount the source code from your workers.

However, compiling a language interpreter is not an easy task. To simplify this process, wws relies by default in the WebAssembly Language Runtimes. This projects offers a set of precompiled languages runtimes you can plug and play in projects like wws.

How to manage language runtimes in wws?

You can check the available commands directly in the wws CLI:

wws runtimes --help

Usage: wws runtimes [OPTIONS] <COMMAND>

install Install a new language runtime (like Ruby, Python, etc)
list List all available runtimes to install. By default, it uses the WebAssembly Language Runtime repository
check List of locally installed runtimes
uninstall Uninstall a language runtime
help Print this message or the help of the given subcommand(s)

--repo-url <REPO_URL> Set a different repository URL
--repo-name <REPO_NAME> Gives a name to the given repository URL
-h, --help Print help information

For a more complete documentation, please refer to the Multiple Languages Runtimes section.