Original author(s)Microsoft Dynamic Language Runtime Team
Developer(s).NET Foundation
Initial releaseAugust 31, 2007; 16 years ago (2007-08-31)
Stable release
IronRuby 1.0 / April 12, 2010; 14 years ago (2010-04-12)
Preview release
IronRuby 1.1.3 / March 13, 2011; 13 years ago (2011-03-13)
Written inC#
Operating systemWindows, Linux, macOS
Platform.NET Framework, Mono
TypeRuby programming language compiler[1][2]
LicenseApache License 2.0

IronRuby is an implementation of the Ruby programming language targeting Microsoft .NET Framework. It is implemented on top of the Dynamic Language Runtime (DLR), a library running on top of the Common Language Infrastructure that provides dynamic typing and dynamic method dispatch, among other things, for dynamic languages.

The project is currently inactive, with the last release of IronRuby (version 1.1.3) being in March 2011.


On April 30, 2007, at MIX 2007, Microsoft announced IronRuby, which uses the same name as Wilco Bauwer's IronRuby project with permission.[3] It was planned to be released to the public at OSCON 2007.[4]

On July 23, 2007, as promised, John Lam and the DLR Design Team presented the pre-Alpha version of the IronRuby compiler at OSCON. He also announced a quick timeline for further integration of IronRuby into the open source community.[5]

On August 31, 2007, John Lam and the DLR Design Team released the code in its pre-alpha stage on RubyForge.[6] The source code has continued to be updated regularly by the core Microsoft team (but not for every check-in). The team also does not accept community contributions for the core Dynamic Language Runtime library, at least for now.[7]

On July 24, 2008, the IronRuby team released the first binary alpha version, in line with OSCON 2008.[8] On November 19, 2008, they released a second Alpha version.

The team actively worked to support Rails on IronRuby.[9][10] Some Rails functional tests started to run, but a lot of work still needed to be done to be able to run Rails in a production environment.[11]

On May 21, 2009, they released 0.5 version in conjunction with RailsConf 2009. With this version, IronRuby could run some Rails applications, but still not on a production environment.[12]

Version 0.9 was announced as OSCON 2009.[13] This version improved performance.[14] Version 1.0 RC1 became available on November 20, 2009.[15]

Version 1.0 became available on April 12, 2010, in two different versions:

The IronRuby team planned to support Ruby 1.8.6 only for 1.0 point releases, and 1.9 version only for upcoming 1.x releases, skipping support for Ruby 1.8.7.[17][18]

In July 2010, Microsoft let go Jimmy Schementi, one of two remaining members of the IronRuby core team, and stopped funding the project.[19][20] In October 2010 Microsoft announced the Iron projects (IronRuby and IronPython) were being changed to "external" projects and enabling "community members to make contributions without Microsoft's involvement or sponsorship by a Microsoft employee".[21]

The last published release of IronRuby was on March 13, 2011 as version 1.1.3.[22]


Mono support

IronRuby may run as well on Mono as it does on Microsoft Common Language Runtime (CLR),[23] but as the IronRuby team only tests it with the CLR on Windows.,[24] it may not build on Mono depending on the build.[25][26][27]

.NET interoperability

The interoperability between IronRuby classes and regular .NET Framework classes is very limited because many Ruby classes are not .NET classes.[28] However, better support for dynamic languages in .NET 4.0 may increase interoperability in the future.[29][30]

Silverlight support

IronRuby was supported on Silverlight. It could be used as a scripting engine in the browser just like the JavaScript engine.[31] IronRuby scripts were passed like simple client-side JavaScript-scripts in <script>-tags. It is then also possible to modify embedded XAML markup.[32]

The technology behind this was called Gestalt.[33]

//DLR initiation script.
<script src="" type="text/javascript">

//Client-side script passed to IronRuby and Silverlight.
<script type="text/ruby">
    window.Alert("Hello from Ruby")

The same worked for IronPython.[34]

Testing infrastructure

IronRuby integrated RubySpec, which is a project to write a complete, executable specification for the Ruby programming language. The IronRuby Git repo includes a copy of the RubySpec tests, including the MSpec test framework.[35]


IronRuby was previously released under the Microsoft Public License, which is OSI-certified BSD-style license.[36]

On July 16, 2010, Microsoft re-licensed IronRuby along with the DLR under the Apache License 2.0.[37]

Further reading

See also


  1. ^ S. Somasegar. "Early look at IronRuby". Retrieved July 25, 2007.
  2. ^ "RubyForge: IronRuby: Project Info". Archived from the original on September 25, 2016. Retrieved September 7, 2007.
  3. ^ Wilco Bauwer. "Microsoft's Iron Ruby". Archived from the original on September 29, 2007. Retrieved July 24, 2007.
  4. ^ John Lam. "Microsoft and IronRuby". Archived from the original on June 12, 2007. Retrieved June 18, 2007.
  5. ^ John Lam. "A First Look at IronRuby". Archived from the original on July 26, 2007. Retrieved July 23, 2007.
  6. ^ Lam, John. "IronRuby on Rubyforge!". Archived from the original on September 3, 2007. Retrieved August 31, 2007. Today, you must check the source code out of the IronRuby Subversion repository on Rubyforge. You will need a Subversion client; we recommend TortoiseSVN. To build the sources from the command line, you must also have Ruby installed on your computer already
  7. ^ Lam, John (April 29, 2008). "Regarding IronRuby... How true it sounds from this blog". Archived from the original on March 16, 2009. Retrieved May 25, 2008. The DLR does not accept contributions from the community (...) Today we do not push to SVN on every successful SNAP check-in
  8. ^ Lam, John (July 24, 2008). "IronRuby at OSCON". Archived from the original on August 7, 2008. Retrieved August 4, 2008. We're shipping our first binary release. In this package, we're taking a "batteries included" approach and shipping the Ruby standard libraries in it
  9. ^ "IronRuby on Rails". Archived from the original on May 29, 2009. Retrieved May 25, 2008.
  10. ^ Lam, John (May 24, 2008). "IronRuby r112 is out". Archived from the original on March 16, 2009. Retrieved May 25, 2008.
  11. ^ Lam, John (May 25, 2008). "IronRuby / Rails Question". Archived from the original on March 17, 2009. Retrieved May 25, 2008. I don't think we're near the end game yet :) We're barely able to run Rails functional tests now, and there's a lot more library work to be done before we can start thinking about deployment
  12. ^ Schementi, Jimmy (May 25, 2008). "IronRuby at RailsConf 2009". Retrieved May 25, 2008. IronRuby running Rails is not new, but doing it well or completely – is. IronRuby can now run real Rails applications, rather than just toy-hello-world examples. This does not mean IronRuby on Rails is ready for production, but it's a great measure of forward progress
  13. ^ "IronRuby 0.9". July 23, 2009. Archived from the original on May 12, 2009. Retrieved August 3, 2009.
  14. ^ Cangiano, Antonio (August 3, 2009). "Comparing the performance of IronRuby, Ruby 1.8 and Ruby 1.9 on Windows". Retrieved August 3, 2009.
  15. ^ "IronRuby 1.0RC1". November 20, 2009. Archived from the original on December 21, 2009. Retrieved December 29, 2009.
  16. ^ "IronRuby 1.0 release notes". April 12, 2010. Archived from the original on April 16, 2010. Retrieved April 17, 2010. IronRuby now comes in two flavors - one that runs on top of .NET 4.0, and one that runs on any earlier framework starting with .NET 2.0 SP1. The .NET 4.0 flavor features faster startup time, compatibility with C#'s dynamic keyword, and access to the new features in .NET 4.0. So, the .NET 4.0 flavor is the preferred download now, as the Microsoft .NET Framework 4.0 is publicly available as of today. For Mono compatibility, use the zip file release for 2.0 SP1.
  17. ^ "MRI 1.8.7 compatibility". February 12, 2010. Archived from the original on September 28, 2011. Retrieved March 6, 2010.
  18. ^ "MRI 1.8.7 compatibility". February 14, 2010. Archived from the original on September 28, 2011. Retrieved March 6, 2010. IronRuby 1.0.x releases: ONLY ruby-1.8.6 compatible; IronRuby 1.x releases: ONLY ruby-1.9 compatible
  19. ^ "It's not you, it's me: Microsoft kills IronRuby". InfoWorld. August 11, 2010. Retrieved December 28, 2012.
  20. ^ Schementi, Jimmy (August 6, 2010). ""Start spreading the news": the future of Jimmy and IronRuby". Retrieved December 28, 2012. Overall, I see a serious lack of commitment to IronRuby, and dynamic language on .NET in general. At the time of my leaving Tomas and myself were the only Microsoft employees working on IronRuby
  21. ^ Zander, Jason. "New Components and Contributors for IronPython and IronRuby". Microsoft. Retrieved December 27, 2014.
  22. ^ "IronRuby 1.1.3". March 13, 2011. Archived from the original on May 30, 2013. Retrieved May 19, 2013.
  23. ^ Miguel de Icaza (July 27, 2009). "Improving Mono's compatibility with .NET CLR". Retrieved August 3, 2009. For as long as we remember, most new versions of IronPython, IronRuby or the Dynamic Language Runtime exposed new missing functionality in Mono
  24. ^ Sanghyeon, Seo (August 6, 2008). "IronRuby and Mono". Archived from the original on March 16, 2009. Retrieved September 13, 2008.
  25. ^ Vander Schelden, Wim (September 4, 2008). "IronRuby and Mono". Archived from the original on March 16, 2009. Retrieved September 13, 2008.
  26. ^ Hall, Ben (January 23, 2009). "DLR Daily Builds (including IronRuby)". Archived from the original on March 15, 2009. Retrieved January 23, 2009.
  27. ^ Porto Carrero, Ivan (May 26, 2009). "mono builds". Archived from the original on February 23, 2012. Retrieved June 5, 2009.
  28. ^ Hagenlocher, Curt (December 16, 2008). "Xna+IronRuby+RubyNewb=headache". Archived from the original on March 16, 2009. Retrieved December 20, 2008.
  29. ^ Brotherus, Robert (December 12, 2008). "WPF databinding with ruby objects". Archived from the original on March 25, 2009. Retrieved December 13, 2008.
  30. ^ "Dynamic .NET - Creating Interactive Bing Maps with Silverlight and IronRuby".
  31. ^ IronRuby in the browser -
  32. ^ "Building a WPF Application in IronRuby". InfoQ.
  33. ^ Schementin, Jimmy (July 22, 2009). "Gestalt: Ruby and Python in the browser, again". Retrieved January 19, 2018.
  34. ^ "Silverlight: Embed IronRuby/DLR Scripting within XAML using IValueConverter and Custom UserControl | Chris Pietschmann".
  35. ^ "RubySpec". GitHub. Retrieved October 23, 2010. The IronRuby GIT repo includes a copy of the RubySpec tests, including the MSpec test framework, under External.LCA_RESTRICTED\Languages\IronRuby\mspec. This makes it easy to modify existing tests or write new tests, and fix the bugs in the IronRuby sources, all in a single commit to the IronRuby repo.
  36. ^ Bort, Julie (April 14, 2010). "After three years effort, Microsoft's open source IronRuby stable and available". Network World.
  37. ^ "IronRuby License". July 16, 2010. Archived from the original on December 6, 2010. Retrieved July 27, 2010.