Free Education Software
MediaWiki
MediaWiki is a free and open source wiki engine used by thousands of organizations and websites across the globe. It's the software that powers Wikipedia, which was released as a free and open source project under the name MediaWiki, a year after the release of Wikipedia. The software allows people to collect and organize knowledge in cooperation with one another, and make it available on the web. MediaWiki is now built by a community of open source developers and provides plugins can be used to extend the software further. Allowing sister sites like Wiktionary, Wikimedia Commons and Wikidata to utilize the same code base.
MoinMoin
MoinMoin is a free and open-source, Python-based WikiEngine thate features an extensible core. With MoinMoin you can create self-hosted wikies and informational resource sites. MoinMoin's extensible core allow for plugins to be installed to further extend the capability of the software. Allowing you to install auth plugins for custom authentication, filter plugins for indexing file attachments of different mimetypes, parsers for new input formats formatters to produce different output formats than HTML, themes xmlrpc and CMS solutions.
XWiki
Developed for more than 10 years, XWiki is a long standing project trusted by individuals and high profile corporations. XWiki is a free and open source Wiki software written in Java and released under the GNU Lesser General Public License. XWiki provides a WYSIWYG editing, OpenDocument based document import/export, semantic annotations and tagging, and advanced permissions management fit for enterprise use. The extensible XWiki platform allow you to customaize and improve your Wiki as the content, userbase or usecase grows and evolves.
Stack Overflow
Stack Overflow is the largest, most trusted question and answers platform and online community for developers to learn, share their programming knowledge, and build their careers.
Zim
Zim is a graphical text editor used to maintain a collection of wiki pages. Each page can contain links to other pages, simple formatting and images. Pages are stored in a folder structure, like in an outliner, and can have attachments. Creating a new page is as easy as linking to a nonexistent page.
Openki
Openki is an interactive web-platform under development with the ambition to facilitate a barrier-free access to education for everyone. The platform facilitates the organization of peer-to-peer courses.
ReadTheDocs
ReadTheDocs is a huge resource that millions of developers rely on for software documentation. With ReadtheDocs it simple to create documentation for your development project that will be hosted free, forever. ReadTheDocs integrates with your favorite version control system, be it Git, Mercurial, Bazaar, or Subversion. Allowing you to push documentation along with project updates through your CI/CD pipeline.
Notable
Notable simple yet powerful Markdown editor that features multi-cursors, a minimap and best-in-class syntax highlighting.
Wiki.js
With Wiki.js you can run a blazing fast Wiki built with performance in mind. Wiki.js is an extensible, free and open source Wiki software written in JavaScript. Wiki.js brings a modern approach to documentation and Wiki writing, it provides a simple to use WYSIWYG editor, a Markdown editor and a visual builder to please all types of workflows. All content moderation is also tracked on a Wiki.js-powered site, which means that you can an revert to a previous state or recover a deleted page at any time and get a broad overview of content evolution. Allowing you to visually compare two versions of the same page to see exactly what changed. Wiki.js runs on virtually any platform and is compatible with either PostgreSQL, MySQL, MariaDB, MS SQL Server or SQLite.