Trilium Notes

Trilium Notes is a free and open-source, cross-platform hierarchical note-taking app for building large personal knowledge bases. It runs on macOS, Linux, and Windows, can be used locally, and can sync with a self-hosted server to access notes anywhere.

Notes are arranged in an arbitrarily deep tree, and a note can appear in multiple places through cloning. The editor supports WYSIWYG text with tables, images, math, and markdown autoformat, plus code notes with syntax highlighting. It also includes full-text search, note hoisting, versioning, attributes for querying and scripting, per-note encryption, sharing, relation maps, mind maps, geo maps, a web clipper, and a REST API.

Now maintained by the TriliumNext community, Trilium ships desktop binaries and a server web interface that runs under Docker. The web UI is nearly identical to the desktop app, and a touch-optimized mobile frontend works from any browser. It scales well past 100,000 notes and offers OpenID and TOTP login.