Yukihiro Matsumoto ("Matz") started working on Ruby on February 24, 1993, and released it to the public in 1995.

The RubySpec project has independently created a large test suite that captures 1.8.6/1.8.7/1.9 behavior as a reference conformance tool.

As a result of the limited uptake by the MRI developers, RubySpec project has been discontinued as of end of 2014.

[4] Prior to release 1.9.3, the Ruby interpreter and libraries were distributed as dual-licensed free and open source software, under the GNU General Public License or the Ruby License.

Commonly noted limitations include: Threaded programs cannot use more than a single CPU core due to the Global interpreter lock.