Last Modified
2015-11-14 17:26:31 -0600


What is mruby

mruby is the lightweight implementation of the Ruby language complying to (part of) the ISO standard. Its syntax is Ruby 1.9 compatible.

mruby can be linked and embedded within your application. We provide the interpreter program “mruby” and the interactive mruby shell “mirb” as examples. You can also compile Ruby programs into compiled byte code using the mruby compiler “mrbc”. All those tools reside in the “bin” directory. “mrbc” is also able to generate compiled byte code in a C source file, see the “mrbtest” program under the “test” directory for an example.

This achievement was sponsored by the Regional Innovation Creation R&D Programs of the Ministry of Economy, Trade and Industry of Japan.

How to get mruby

The stable version 1.1.0 of mruby can be downloaded via the following URL:

The latest development version of mruby can be downloaded via the following URL:

The trunk of the mruby source tree can be checked out with the following command:

$ git clone

mruby home-page

The URL of the mruby home-page is:

Mailing list

We don’t have mailing list, but you can use GitHub issues.

How to compile and install (mruby and gems)

See the doc/guides/ file.

Running Tests

To run the tests, execute the following from the project’s root directory.

$ make test


$ ruby ./minirake test

How to customize mruby (mrbgems)

mruby contains a package manager called mrbgems. To create extensions in C and/or Ruby you should create a GEM. For a documentation of how to use mrbgems consult the file doc/mrbgems/ For example code of how to use mrbgems look into the folder examples/mrbgems/.


mruby is released under the MIT License.

Note for License

mruby has chosen a MIT License due to its permissive license allowing developers to target various environments such as embedded systems. However, the license requires the display of the copyright notice and license information in manuals for instance. Doing so for big projects can be complicated or troublesome. This is why mruby has decided to display “mruby developers” as the copyright name to make it simple conventionally. In the future, mruby might ask you to distribute your new code (that you will commit,) under the MIT License as a member of “mruby developers” but contributors will keep their copyright. (We did not intend for contributors to transfer or waive their copyrights, Actual copyright holder name (contributors) will be listed in the AUTHORS file.)

Please ask us if you want to distribute your code under another license.

How to Contribute

See the contribution guidelines, and then send a pull request to We consider you have granted non-exclusive right to your contributed code under MIT license. If you want to be named as one of mruby developers, please include an update to the AUTHORS file in your pull request.

Commenting is here to help enhance the documentation. For example, code samples, or clarification of the documentation.

If you have questions about Ruby or the documentation, please post to one of the Ruby mailing lists. You will get better, faster, help that way.

If you wish to post a correction of the docs, please do so, but also file bug report so that it can be corrected for the next release. Thank you.

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