slate VS API-Portal

Slate (Free)

https://github.com/slatedocs/slate this ! Big company use it ( stripe etc )

The second most common question being "What framework does Stripe use to build their documentation?" and the answer has unfortunately always been "They use a custom setup they built themselves and isn't available." － so then Slate gets brought up as a suitable replacement

DocuAPI is a multilingual API documentation theme for Hugo created and maintained by Bjørn Erik Pedersen, the lead maintainer and co-creator of Hugo itself. It’s built on top of the Slate API docs generator, which itself was inspired by Stripe’s and PayPal’s API docs. The JavaScript section of DocuAPI has been rewritten from Jquery to AlpineJS.​​​​​​

I've used Slate to document APIs which similarly will produce a local website. You can host that privately or there's built in support to push to github pages if you're hosting it in a github repo. The documentation itself is all written in markdown and managed separate from your API code.

Clone/inspired by stripe docs: https://github.com/slatedocs/slate

If you are going to use Slate from the console you need to install it, along with all its prerequisites, as described here. In Ubuntu you can execute the commands:

Slate - API Generator