Standard Notes is an open-source note app with end-to-end encryption that has been running for more than ten years, with a public codebase and independent security audits. The permanently free tier covers encryption, unlimited devices, offline access, tags, per-note passwords, daily encrypted backups and two-step verification, and every note can leave as plain text.

An open source, self-hosted notebook organised as a tree rather than a flat list. Notes can be cloned into several branches, edited in place with tables, diagrams and formulas, scripted with JavaScript, and reached through a REST API. Run the desktop client or your own server.