DP Code Development
There are numerous pieces of open-source software that are used in service of Distributed Proofreaders' mission of Preserving History One Page at a Time. This includes tools that Project Managers use to prepare the OCR text for being loaded into a new project, the code that runs pgdp.net, tools that help Post-Processors prepare ebooks for being published to Project Gutenberg, and many more.
Most of this code is hosted on GitHub under the Distributed Proofreaders organization.
pgdp.net
The source code that drives pgdp.net is Open Source software under the GPLv2 license. It is hosted on GitHub under the Distributed Proofreaders organization. The code is written primarily in PHP, a web-centric interpreted language. If you've ever done any Perl, python, or C coding you'll find PHP very familiar.
For more information on this code and how to contribute see DP Code Development: dproofreaders.
Guiguts 2.0 (guiguts-py)
guiguts-py is an in-development python version of Guiguts. It is currently at beta 3, and soon to be full production release.
guiguts
The original guiguts is no longer being actively maintained. It is a Perl/Tk text editor designed for editing and formatting public domain material for inclusion at Project Gutenberg. The code is still available at guiguts. Because of increasing difficulties installing the Perl/Tk dependencies, the decision was made to create a python version (see the Guiguts 2.0 (guiguts-py) section above. The Guiguts 1 Manual is hosted on the DP wiki.
ppwb
ppwb is the Post-Processor's Workbench, a collection of tools to help Post-Processors make a variety of checks on their finished ebooks before uploading to Project Gutenberg.
guiprep
guiprep is a perl script by the author of Guiguts that is used to prepare OCR text for uploading to DP.