MkDocs
MkDocs is a fast, simple and downright gorgeous static site generator that’s geared towards building project documentation. Documentation source files are written in Markdown, and configured with a single YAML configuration file.
MkDocs builds completely static HTML sites that you can host on GitHub pages, Amazon S3, or anywhere else you choose. There’s a stack of good looking themes available for MkDocs. The built-in dev-server allows you to preview your documentation as you’re writing it. It will even auto-reload and refresh your browser whenever you save your changes. Get your project documentation looking just the way you want it by customizing the theme and/or installing some plugins.
22 Alternatives To MkDocs
Antora
A static site generator for creating documentation sites from AsciiDoc content aggregated from…

ApiGen
ApiGen is the tool for creating professional API documentation from PHP source code, similar to…

Confluence
Confluence is content collaboration software that changes how modern teams work
DocFX
A documentation generation tool for API reference and Markdown files!

Docsify
Docsify is an engagement based sales automation tool which provides smart scoring solution and pipeline automation capabilities.
Docusaurus
Easy to maintain open source documentation websites
DokuWiki
DokuWiki is a simple to use and highly versatile Open Source wiki software that doesn’t require a database. It is loved by users for its clean and readable syntax. The ease of maintenance, backup and integration makes it an administrator’s favorite.
Doxygen
Doxygen is a tool for generating documentation from annotated C++ sources, as well as other popular…
GitBook
Modern Publishing, Simply taking your books from ideas to finished, polished books.

GitHub Pages
A free, static web host for open-source projects on GitHub
Grav
The modern open source flat-file CMS
HelpNDoc
What is HelpNDoc ? Easy to use yet powerful help authoring environment which can generate various documentation formats from a single source.

Jekyll
Jekyll is a simple, blog aware, static site generator.

ReadMe
A collaborative developer hub for your API or code.

ReadTheDocs
Spend your time on writing high quality documentation, not on the tools to make your documentation work.

SkyDocs
SkyDocs is a lightweight static documentation builder with MarkDown.

Sphinx Documentation Generator
Sphinx is a tool that makes it easy to create intelligent and beautiful documentation, written by…

TiddlyWiki
TiddlyWiki — a non-linear personal web notebook
code_doc
Hosted documentation and artifacts server
mdbook
Gitbook alternative in Rust