ruby.wasm

ruby.wasm is a collection of WebAssembly ports of CRuby. It enables running Ruby applications in browsers, WASI compatible WebAssembly runtimes, and Edge Computing platforms.

Try ruby.wasm (no installation needed)

Try ruby.wasm on TryRuby in your browser.

Quick Links

Quick Example: Ruby in a Web browser

Create and save an index.html page with the following contents:

<html>
  <script src="https://cdn.jsdelivr.net/npm/@ruby/4.0-wasm-wasi@2.9.4/dist/browser.script.iife.js"></script>
  <script type="text/ruby">
    require "js"

    puts RUBY_VERSION # (Printed to the Web browser console)
    JS.global[:document].write "Hello, world!"
  </script>
</html>

Quick Example: How to package your Ruby application as a WASI application

Dependencies: wasmtime

$ gem install ruby_wasm
# Download a prebuilt Ruby release
$ curl -LO https://github.com/ruby/ruby.wasm/releases/latest/download/ruby-4.0-wasm32-unknown-wasip1-full.tar.gz
$ tar xfz ruby-4.0-wasm32-unknown-wasip1-full.tar.gz

# Extract ruby binary not to pack itself
$ mv ruby-4.0-wasm32-unknown-wasip1-full/usr/local/bin/ruby ruby.wasm

# Put your app code
$ mkdir src
$ echo "puts 'Hello'" > src/my_app.rb

# Pack the whole directory under /usr and your app dir
$ rbwasm pack ruby.wasm --dir ./src::/src --dir ./ruby-4.0-wasm32-unknown-wasip1-full/usr::/usr -o my-ruby-app.wasm

# Run the packed scripts
$ wasmtime my-ruby-app.wasm /src/my_app.rb
Hello

npm packages (for JavaScript host environments)

See the README.md of each package for more detail and its usage.

Package	Description	npm
@ruby/4.0-wasm-wasi	CRuby 4.0 built on WASI with JS interop support
@ruby/3.4-wasm-wasi	CRuby 3.4 built on WASI with JS interop support
@ruby/3.3-wasm-wasi	CRuby 3.3 built on WASI with JS interop support
@ruby/3.2-wasm-wasi	CRuby 3.2 built on WASI with JS interop support
@ruby/head-wasm-wasi	HEAD CRuby built on WASI with JS interop support
@ruby/head-wasm-emscripten	HEAD CRuby built on Emscripten (not well tested)

Prebuilt binaries

This project distributes prebuilt Ruby binaries in GitHub Releases. A build is a combination of ruby version, profile, and target.

Supported Target Triples

Triple	Description
`wasm32-unknown-wasip1`	Targeting WASI Preview1 compatible environments (e.g. Node.js, browsers with polyfill, wasmtime, and so on)
`wasm32-unknown-emscripten`	Targeting JavaScript environments including Node.js and browsers

Profiles

Profile	Description
`minimal`	No standard extension libraries (like `json`, `yaml`, or `stringio`)
`full`	All standard extension libraries

Notable Limitations

The current WASI target build does not yet support Thread related APIs. Specifically, WASI does not yet have an API for creating and managing threads yet.

Also there is no support for networking. It is one of the goals of WASI to support networking in the future, but it is not yet implemented.

Contributing

See CONTRIBUTING.md for how to build and test, and how to contribute to this project. Bug reports and pull requests are welcome on GitHub at https://github.com/ruby/ruby.wasm