MkDocs vs Sphinx: What are the differences?
Developers describe MkDocs as "A static site generator *". It 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. 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. On the other hand, *Sphinx** is detailed as "Open source full text search server, designed from the ground up with performance, relevance (aka search quality), and integration simplicity in mind". Sphinx lets you either batch index and search data stored in an SQL database, NoSQL storage, or just files quickly and easily — or index and search data on the fly, working with Sphinx pretty much as with a database server. A variety of text processing features enable fine-tuning Sphinx for your particular application requirements, and a number of relevance functions ensures you can tweak search quality as well.
MkDocs belongs to "Static Site Generators" category of the tech stack, while Sphinx can be primarily classified under "Search Engines".
According to the StackShare community, Sphinx has a broader approval, being mentioned in 42 company stacks & 73 developers stacks; compared to MkDocs, which is listed in 5 company stacks and 8 developer stacks.