What it does
Cairn is a free, open-source Markdown note app for Linux, Windows, and Android. Each notebook is an ordinary folder of Markdown files that Cairn reads and writes directly. The app provides live preview, source and reading views, wiki links, backlinks, full-text search, tags, and a graph view. Optional end-to-end encrypted synchronization runs through a server the user operates.
Keep a notebook as a folder of files
Open a folder as a notebook and create ordinary .md notes inside it. Cairn's manual describes live preview, source and reading modes, wiki-link autocomplete, backlinks, search filters, and a graph view. That makes the app a fit for a personal knowledge base without requiring a proprietary note database.
If notes need to move between devices, Cairn's sync documentation describes an optional end-to-end encrypted server that the user runs. The site says conflicting edits become separate copies and version history can restore an older note. This is a more hands-on setup than an account-based sync service. The release page lists version 1.4.3 and states that there are no macOS builds. No installation, sync server, or conflict recovery was tested.
Strengths
- Notes are plain Markdown files in folders that can also be handled by other editors and backup tools.
- Backlinks, tag-aware search, and a graph view support connected-note workflows.
- Optional synchronization is end-to-end encrypted and can be self-hosted.
Watch out for
- Synchronization requires running a separate server rather than signing in to a turnkey cloud service.
- The official release notes say there are no macOS builds.
Best for
- Keeping a local Markdown knowledge base on Linux, Windows, or Android
- Users willing to self-host encrypted sync rather than use a vendor cloud
Sources
- Cairn Notes | Official Product Homepage (Oct 25, 2026)
- Cairn Manual v1.4.3 (Oct 25, 2026)
- Cairn Releases | GitHub (Oct 25, 2026)
- MIT License | Cairn (Oct 25, 2026)
- Known Limits | Cairn Manual (Oct 25, 2026)