Every wiki page lives as a plain-text file in a standard Git repository, giving you full version history, branching, merging, and the freedom to edit with any text editor or IDE alongside the web interface. Originally built by GitHub's founders as the engine behind GitHub's own wiki feature, Gollum supports Markdown, AsciiDoc, reStructuredText, Org-mode, Textile, MediaWiki, Creole, and Pod markup formats with live preview rendering as you type. PlantUML and Mermaid diagrams render inline for architecture documentation, MathJax handles mathematical notation, and BibTeX integration via Pandoc provides academic citation management. YAML frontmatter controls per-page sidebars, headers, footers, and table of contents generation. CriticMarkup annotations enable editorial review workflows with tracked insertions, deletions, substitutions, and comments. Macros extend pages with dynamic content injection, file includes, and navigation helpers. The wiki maintains compatibility with GitHub and GitLab wiki repositories, so teams can clone existing platform wikis for local editing and offline access. The official Docker image at gollumwiki/gollum exposes port 4567 with volume-mounted repositories, requiring roughly 170 MB of container storage and minimal RAM. Authentication integrates via OmniAuth supporting GitHub, GitLab, Google, and other OAuth providers. Over 14,300 stars on GitHub since 2009. MIT licensed.