BookStack is an easy-to-use, self-hosted platform for organizing and storing information. BookStack is completely free and open source, and it is MIT licensed. The source code is available on GitHub. It is free to download and install your own bookstack instance. BookStack was built with simplicity in mind. BookStack’s content is searchable. Searches can be made at book level, across all books, chapters, pages, and even across entire books. You can link directly to any paragraph to keep your documentation connected. BookStack can be configured to suit your needs. You can modify the name, logo, and registration options. You can also modify whether the entire system is visible to the public. BookStack is built on PHP and the Laravel framework. It uses MySQL to store data. BookStack runs happily on a $5 Digital Ocean VPS.
https://www.bookstackapp.com/