Codex is described as 'simple file-based Markdown documentation platform built on top of Laravel. It's completely customizable and dead simple to use to create beautiful documentation' and is an app in the Development category. There are more than 10 alternatives to Codex for a variety of platforms, including Linux, Self-Hosted solutions, Mac, Windows and BSD. The best alternative is Doxygen, which is both free and Open Source. Other great apps like Codex are Daux.io (Free, Open Source), Slate API Docs Generator (Free, Open Source), Raneto (Free, Open Source) and Presidium (Free, Open Source).
Doxygen is a tool for generating documentation from annotated C++ sources, as well as other popular programming languages like C, Objective-C, C#, PHP, Java, Python, IDL (CORBA, Microsoft, and UNO/OpenOffice flavors), Fortran, VHDL, Tcl, and to some extent D.
Daux.io is a documentation generator that uses a simple folder structure and Markdown files to create custom documentation on the fly. It helps you create great looking documentation in a developer friendly way.
Easy Install and Upgrade. npm makes installation and upgrade a, trivial, single command activity. No need to modify your content during upgrades. Instant Publication.. Author and review content on your desktop, then publish via github pages with a single checkin.
LuaDoc is a documentation generator tool for Lua source code. It parses the declarations and documentation comments in a set of Lua source files and produces a set of XHTML pages describing the commented declarations and functions.
Extracts all docblocks with an @export, so you can @import into .md files. You can write your documentation anywhere in your code, so it's all maintained in one place. PHP only, other languages coming soon.