Wiki.js is described as 'Write your content in the widely used and simple Markdown format, using the built-in visual editor. Unlike other wiki software that save content in a database with a difficult to extract format, Wiki.js saves all your content directly into Markdown (' and is an app in the Development category. There are more than 50 alternatives to Wiki.js for a variety of platforms, including Online / Web-based, Windows, Self-Hosted solutions, Mac and Linux. The best alternative is Notion. It's not free, so if you're looking for a free alternative, you could try TiddlyWiki or BookStack. Other great apps like Wiki.js are MediaWiki (Free, Open Source), Nuclino (Freemium), DokuWiki (Free, Open Source) and Walling (Freemium).
BookStack is a free and open source knowledge management platform built on PHP. The system has been built around simplicity to ensure that adding information to it is not a chore. The content structure is built on the metaphors of Books, Chapters & Pages.
MediaWiki is a free software wiki package written in PHP, originally for use on Wikipedia. It is now used by several other projects of the non-profit Wikimedia Foundation and by many other wikis, including this website, the home of MediaWiki.
Nuclino is a unified workspace where teams can bring all their knowledge, docs, and projects together in one place. It’s a modern, simple, and blazingly fast way to collaborate, without the chaos of files and folders, context switching, or silos.