Ask HN: Do you know a good Knowledge Base service or software?

You just built a SaaS product, but it seems it is not intuitive enough for everyone on this planet, so people can get lost, and you're getting asked the same questions often (where do I find this, how do I do that...). You're starting to think you should have a Knowledge Base where people can search for their question and most of the time end up on an article that will answer their issue.

Do you know a good software or even paid service to build that kind of knowledge base?

In my (short) experience, what I'd expect from such a software would be:

- a nice and efficient search experience, to find the right article even with a more-or-less approximative search from a non-tech-savvy user

- easy to maintain and update: Markdown, support for multiple languages... Maybe even an API to be able to synchronize some articles directly from a product's codebase (e.g. API documentation)

- navigation between "similar" articles

The only service I've found that tries to do that is Zendesk, but in my experience it is far from perfect and feels like 10 years ago, for example there is no Markdown (and the HTML editor is not very "permissive", deleting THEAD tags for example), despite Markdown being available in the rest of Zendesk features.

There's also the possibility that I'm looking in the wrong direction from the start, and maybe the Knowledge Base approach is not the best to answer this use case.

Thanks in advance for your insights :)