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A high performance implementation of the Ruby programming language. Built on the GraalVM by Oracle Labs.

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TruffleRuby is the GraalVM high-performance implementation of the Ruby programming language.

Getting Started

There are three ways to install TruffleRuby releases and nightly builds:

  • Via GraalVM, which includes support for other languages such as JavaScript, R, and Python, and supports both the Native and JVM configurations. Inside GraalVM will then be a

    command that runs TruffleRuby. We recommend that you use a Ruby manager to use TruffleRuby inside GraalVM.
  • Via your Ruby manager/installer (RVM, rbenv, chruby, ruby-build, ruby-install). This contains only TruffleRuby, in the Native configuration, making it a smaller download. It is meant for users who only want a Ruby implementation and are already using a Ruby manager.

  • Via the standalone distribution as a simple binary tarball.

We recommend trying TruffleRuby nightly builds which contain the latest fixes and improvements:

RVM:    $ rvm install truffleruby-head
rbenv:  $ rbenv install truffleruby-dev
chruby: $ ruby-build truffleruby-dev ~/.rubies/truffleruby-dev

See the Ruby installers documentation for more details.

Testing TruffleRuby in CI is easy. On TravisCI, you can use:

language: ruby
  - truffleruby # or truffleruby-head

And on GitHub Actions:

- uses: ruby/[email protected]
    ruby-version: truffleruby # or truffleruby-head

See Testing TruffleRuby in CI for more details and other CIs.

You can use

to install gems, as usual.

Please report any issues you might find on GitHub.


TruffleRuby aims to:

  • Run idiomatic Ruby code faster.
    • TruffleRuby is the fastest Ruby implementation for many CPU-intensive benchmarks.
  • Run Ruby code in parallel.
    • TruffleRuby does not have a global interpreter lock and runs Ruby code in parallel.
  • Support C extensions.
    • Many C extensions work out of the box, including database drivers.
  • Add fast and low-overhead interoperability with languages like Java, JavaScript, Python, and R.
  • Provide new tooling, such as debuggers and monitoring, that works across languages.
  • Provide all of the above while maintaining very high compatibility with the standard implementation of Ruby.

TruffleRuby Runtime Configurations

There are two main runtime configurations of TruffleRuby, Native and JVM, which have different trade-offs.

| Configuration: | Native (

, default) | JVM (
) | | ------------------ | ------------: | ------------: | | Time to start TruffleRuby | about as fast as MRI startup | slower | | Time to reach peak performance | faster | slower | | Peak performance (also considering GC) | good | best | | Java host interoperability | needs reflection configuration | just works |

To find out which runtime configuration is being used, run

ruby --version
on the command line, or check the value of
in Ruby code. Runtime configurations are further detailed in Deploying TruffleRuby.

System Compatibility

TruffleRuby is actively tested on the following systems:

  • Oracle Linux 7
  • Ubuntu 18.04 LTS
  • Ubuntu 16.04 LTS
  • Fedora 28
  • macOS 10.14 (Mojave)
  • macOS 10.15 (Catalina)


  • AMD64 (aka
    ): Supported
  • AArch64 (aka
    ): Experimental, C extensions do not work yet on AArch64

You may find that TruffleRuby will not work if you severely restrict the environment, for example, by unmounting system filesystems such as



  • make and gcc for building C and C++ extensions
  • libssl for the
    C extension
  • zlib for the
    C extension

Without these dependencies, many libraries including RubyGems will not work. TruffleRuby will try to print a nice error message if a dependency is missing, but this can only be done on a best effort basis.

You may also need to set up a UTF-8 locale.

See the contributor workflow document if you wish to build TruffleRuby from source.

Current Status

We recommend that people trying TruffleRuby on their gems and applications get in touch with us for help.

TruffleRuby can run Rails and is compatible with many gems, including C extensions. However, TruffleRuby is not 100% compatible with MRI 2.7 yet. Please report any compatibility issues you might find. TruffleRuby passes around 97% of ruby/spec, more than any other alternative Ruby implementation.

TruffleRuby might not be fast yet on Rails applications and large programs. Notably, large programs currently take a long time to warmup on TruffleRuby and this is something the TruffleRuby team is currently working on. Large programs often involve more performance-critical code so there is a higher chance of hitting an area of TruffleRuby which has not been optimized yet.


TruffleRuby has the same version, and is released at the same time as GraalVM. There is a release every 3 months. See the release roadmap.

Migration from MRI

TruffleRuby should in most cases work as a drop-in replacement for MRI, but you should read about our compatibility.

Migration from JRuby

For many use cases TruffleRuby should work as a drop-in replacement for JRuby. However, our approach to integration with Java is different to JRuby so you should read our migration guide.


Extensive user documentation is available in


See our source code repository and contributor documentation to contribute to TruffleRuby. In particular, see the contributor workflow document for how to build and run TruffleRuby.


The best way to get in touch with us is to join the

channel on GraalVM Slack. You can also Tweet to @TruffleRuby, or email [email protected].

Please report security vulnerabilities via the process outlined in the reporting vulnerabilities guide, rather than by something public such as a GitHub issue or a Gitter conversation.

Mailing List

Announcements about GraalVM, including TruffleRuby, are made on the graal-dev mailing list.


The main authors of TruffleRuby ordered by first contribution are: Chris Seaton, Benoit Daloze, Kevin Menard, Petr Chalupa, Brandon Fish, Duncan MacGregor, Christian Wirth, Rafael França, Alan Wu, Nicolas Laurent, Carol Chen, Nikolay Sverchkov, and Lillian Zhang.


See SECURITY for how to report security vulnerabilities to Oracle. For known vulnerabilities in Ruby, please refer to the known-cves file.


TruffleRuby is copyright (c) 2013-2021 Oracle and/or its affiliates, and is made available to you under the terms of any one of the following three licenses:

  • Eclipse Public License version 2.0, or
  • GNU General Public License version 2, or
  • GNU Lesser General Public License version 2.1.

For further licensing information, see LICENCE, 3rdpartylicenses, and doc/legal/legal.


TruffleRuby is a fork of JRuby, combined with code from the Rubinius project, and code from the standard implementation of Ruby, MRI.

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