Outline
The best-looking option — and not open source, whatever the lists say.
Outline is a fast, beautifully judged team knowledge base with excellent search, a slash-command editor and Slack integration that people actually use. It is also the entry on this page most often mislabelled. Outline ships under the **Business Source License 1.1**, not an OSI licence: you may self-host it for internal use, but you may not offer it as a competing hosted service, and the licence converts to open source only after a delay. For most companies documenting their own work that changes nothing. If you were planning to build a product on it, it changes everything — and you would not learn that from the directory that told you it was open source.
What it does well
- +Best design and editing experience of anything on this page
- +Search is genuinely fast and good
- +Slack and API integrations that people use daily
- +Self-hostable for ordinary internal use
Where it falls short
- −NOT open source — Business Source License, despite near-universal mislabelling
- −Cannot be offered as a competing hosted service
- −Licence terms can be tightened by the vendor on future versions
- −Smaller plugin ecosystem than Confluence
Outline as an alternative to
Where Outline shows up in our comparisons, and how it ranked.
Outline head-to-head
Straight comparisons against the tools people weigh it against.