Ask HN: What do you use for your hosted knowledge base?

I know that many of the helpdesk services (desk.com, zendesk, groove, helpscout, ...) have a Knowledge Base feature as an add-on. I'm curious if there are any good hosted knowledge base solutions where it isn't an afterthought.

I found supporthero.io and knowledgeowl.com but both seem to be very small companies (just 1 or 2 people) that may not be around for long. Then there's helpjuice.com which looks perfect but starts at $199/month.

I'm curious what folks on HN use.