The Free / Libre / Open Source Web App with the most built-in features
"Software made the wiki way" A full-featured, web-based, multilingual (40+ languages), tightly integrated, all-in-one Wiki+CMS+Groupware, Free Source Software (GNU/LGPL), using PHP, MySQL, Zend Framework, jQuery and Smarty. Tiki can be used to create all kinds of Web applications, sites, portals, knowledge base, intranets, and extranets. Tiki is the Open Source Web Application with the most built-in features. Highly configurable and modular, all features are optional and administered via a web-based interface. Major features include a wiki engine, news articles, discussion forums, newsletters, blogs, file galleries, bug and issue trackers (form generator), polls/surveys and quizzes, banner management system, calendar, maps, mobile , RSS feeds, category system, tags, an advanced themeing engine, spreadsheet, drawings, inter-user messaging, menus, advanced permission system for users and groups, search engine, external authentication, etc. Security reports: security@tiki.org
Open Source Enterprise Wiki and Web Application Platform
Enterprise collaboration platform with over 400 extensions. Users without programming skills can create web applications. 50,000 small businesses, many Fortune 500 companies, and millions of people use TWiki, with installations of 100,000s of pages. Visit http://twiki.org/ for the open source TWiki. The TWiki community is focusing on building the best collaboration platform for the workplace. We invite you to GET INVOLVED! More at http://bit.ly/twGetInv.
Foswiki is an Enterprise wiki, typically used to run a collaboration platform, knowledge base or document management system. Users can create wiki applications using the Topic Markup Language, and developers can extend its functionality with plugins. Foswiki stands for "Free and Open Source" wiki to emphasize its commitment to Open Source software.
WackoWiki is a light and easy to install multilingual Wiki-engine.
WackoWiki is a light and easy to install multilingual Wiki-engine. Supports WYTIWYG-editing, page rights (ACLs), design themes (skins), file upload, email notification and much more. Compatible with PHP 7.0 / 7.2 and MariaDB / MySQL.
Small and Simple Wiki
Wikepage is a small wiki - blog hybrid site generator written in PHP. It runs without a database. It has i18n support, multilanguage site support, password protected pages, table support, css styling, RSS output, and alot of other features
Crabgrass is social networking, group collaboration, and network organizing Web application. It consists of a solid suite of group collaboration tools such as private wikis, task lists, a file repository, and decision making tools.