Wiki.js
Self-hosted team wiki whose pages sync both ways with a Git repository, written in Markdown or a visual editor. 2.x is stable; 3.0 is a PostgreSQL-only beta.
// WIKI
4 entries tagged with "wiki"
// COMPARISONS
1// ENTRIES
3 entries
Outline
Team wiki with live co-editing and nested documents. Source-available under BSL 1.1, and sign-in requires Google, Slack, Microsoft, Discord or an OIDC provider.
BookStack
Team documentation filed into shelves, books, chapters and pages: an MIT-licensed PHP wiki you host yourself on MySQL or MariaDB, with no paid edition.