ruby.wasm is a collection of WebAssembly ports of the CRuby.
See the code
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 on TryRuby in your browser.
Create and save an index.html page with the following contents:
<html>
<script src="https://cdn.jsdelivr.net/npm/@ruby/[email protected]/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>
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
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) |  |
This project distributes prebuilt Ruby binaries in GitHub Releases. A build is a combination of ruby version, profile, and target.
| 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 |
| Profile | Description |
|---|---|
minimal | No standard extension libraries (like json, yaml, or stringio) |
full | All standard extension libraries |
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.
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
(top 24 of 34)
6,963 followers · starred Aug 2024
1,943 followers · starred Dec 2021
3,425 followers · starred Mar 2025
908 followers · starred Feb 2023
ruby.wasm is a collection of WebAssembly ports of the CRuby.
See the code
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 on TryRuby in your browser.
Create and save an index.html page with the following contents:
<html>
<script src="https://cdn.jsdelivr.net/npm/@ruby/[email protected]/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>
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
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) | |
This project distributes prebuilt Ruby binaries in GitHub Releases. A build is a combination of ruby version, profile, and target.
| 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 |
| Profile | Description |
|---|---|
minimal | No standard extension libraries (like json, yaml, or stringio) |
full | All standard extension libraries |
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.
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
(top 24 of 34)
6,963 followers · starred Aug 2024
1,943 followers · starred Dec 2021
3,425 followers · starred Mar 2025
908 followers · starred Feb 2023