LicenseAGPL-3.0-or-later with proprietary Joplin Server licence
Joplin is a free, open-source note-taking and to-do app that keeps Markdown notes in notebooks with tags, works fully offline, and synchronises through user-chosen targets with end-to-end encryption.
Notesnook is an open-source, end-to-end encrypted note-taking app with notebooks, tags, and reminders that works offline across mobile, web, and desktop, syncing through its own cloud from a free tier.
Standard Notes is a free, open-source note-taking app that protects notes and files with audited end-to-end encryption and syncs them across unlimited devices.