pygments.rb is a Ruby wrapper for Pygments syntax highlighter.

pygments.rb works by talking over a simple pipe to a long-lived Python child process. This library replaces github/albino, as well as an older version of pygments.rb that used an embedded Python interpreter.

Each Ruby process that runs has its own 'personal Python'; for example, 4 Unicorn workers will have one Python process each. If a Python process dies, a new one will be spawned on the next pygments.rb request.

System Requirements

  • Python >= 3.5

  • Ruby >= 2.3


Add this line to your application’s Gemfile:

gem 'pygments.rb'

And then execute:

$ bundle install

Or install pygments.rb gem yourself as:

$ gem install pygments.rb


Require pygments.rb module:

require 'pygments'

Highlight a file:

Pygments.highlight(, lexer: 'ruby')

Optionally, pass encoding and other lexer/formatter options via an :options hash:

Pygments.highlight('code', options: {encoding: 'utf-8'})

pygments.rb uses HTML formatter by default. To use a different formatter, specify it via :formatter parameter:

Pygments.highlight('code', formatter: 'bbcode')
Pygments.highlight('code', formatter: 'terminal')

To generate CSS for HTML formatted code, use the Pygments.css method:


To use a specific pygments style, pass the :style option to the Pygments.css method:

Pygments.css(style: 'monokai')

Other Pygments high-level API methods are also available. These methods return arrays detailing all the available lexers, formatters, and styles:


To use a custom pygments installation, specify the path to Pygments.start:


If you’d like logging, set the environmental variable MENTOS_LOG to a file path for your logfile.

You can apply a timeout to pygments.rb calls by specifying number of seconds in MENTOS_TIMEOUT environmental variable or by passing the :timeout argument (takes precedence over MENTOS_TIMEOUT):

Pygments.highlight('code', timeout: 4)


$ ruby bench.rb 50
   Size: 698 bytes
   Iterations: 50
                                                  user     system      total        real
   pygments popen                                0.010000   0.010000   0.020000 (  0.460370)
   pygments popen (process already started)      0.010000   0.000000   0.010000 (  0.272975)
   pygments popen (process already started 2)    0.000000   0.000000   0.000000 (  0.273589)
$ ruby bench.rb 10
   Size: 15523 bytes
   Iterations: 10
                                                  user     system      total        real
   pygments popen                               0.000000   0.000000   0.000000 (  0.819419)
   pygments popen (process already started)     0.010000   0.000000   0.010000 (  0.676515)
   pygments popen (process already started 2)   0.000000   0.010000   0.010000 (  0.674189)


After checking out the repo, run bundle install to install dependencies. Then, run bundle exec rake test to run the tests.

Copyright © Ted Nyman, Aman Gupta, Marat Radchenko, 2012-2021. Free use of this software is granted under the terms of the MIT License.

For the full text of the license, see the LICENSE file.