Developer Documentation
Build product and API documentation.
Every wiki rots the same way: nothing gets deleted, search returns four versions of the same page, and people give up and ask in chat. Confluence optimises for permissions and process. Outline, Nuclino and Slab optimise for finding things quickly, which matters more until you have auditors to answer to. Public API docs are a different job.
Editor's pick
Outline when the team is small and the real pain is search. Confluence earns its weight once you need approvals, audit trails and page-level permissions — and not one day before that.