Logseq is an open-source, local-first knowledge-management app in the same lineage as Roam Research and Obsidian. Notes are stored as plain Markdown (or Org-mode) files on your own machine, organized into an outliner of nested blocks with bidirectional links, page references and a daily-journal workflow. Whiteboards, queries, tasks and PDF annotation are built in, and a graph view shows how everything connects.

The app is free and source-available under the AGPL, with desktop builds for macOS, Windows and Linux plus mobile apps for iOS and Android. Optional Logseq Sync offers end-to-end encrypted sync across devices for paid backers — the core product remains usable forever offline. Active community on GitHub, Discord and the Logseq forum; the team has been shipping publicly for years and the project has substantial third-party plugin and theme ecosystems.