The knowledge base HelpKit is most often weighed against on features, and its opposite on transparency: Document360 sales-gates its tier table where HelpKit publishes every figure. It also owns the articles, priced per project plus per seat, where HelpKit renders a Notion workspace you already own.
Flat monthly knowledge base for teams that want the articles held in one system with a first-party editor, rather than rendered from somewhere else.
Flat monthly plus a per-author charge, so it inverts HelpKit's model: authors are the price driver rather than a cap that comes free with the site.
Also renders documentation from an external source of truth, in its case a Git repository rather than a Notion workspace, but it is priced per seat and sells to engineering teams.
4 of 9 not published by HelpKit, checked