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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:

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/setup-ruby@v1
    ruby-version: truffleruby # or truffleruby-head

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

You can use gem and bundle to install gems, as usual.

Please report any issues you might find on GitHub.


TruffleRuby aims to:

TruffleRuby Runtime Configurations

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

Configuration: Native (--native, default) JVM (--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 RUBY_DESCRIPTION or TruffleRuby.native? in Ruby code. Runtime configurations are further detailed in Deploying TruffleRuby.

System Compatibility

TruffleRuby is actively tested on the following systems:


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


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.


The best way to get in touch with us is to join the #truffleruby channel on GraalVM Slack. You can also Tweet to @TruffleRuby, or email

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 Fran├ža, 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:

For further licensing information, see LICENCE, 3rd_party_licenses, 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.