Notebooks

Joplin

Joplin is a free, open-source, and fully-featured note-taking and to-do application which can handle a large number of markdown notes organized into notebooks and tags. It offers end-to-end encryption and can sync through Nextcloud, Dropbox, and more. It also offers easy import from Evernote and plain-text notes.

Standard Notes

Standard Notes is a simple and private notes app that makes your notes easy and available everywhere you are. It features end-to-end encryption on every platform, and a powerful desktop experience with themes and custom editors. It has also been independently audited (PDF).

Joplin does not support password/pin protection for the application itself or individual notes/notebooks. Data is still encrypted in transit and at the sync location using your master key.

EteSync Notes

EteSync Notes is a secure, end-to-end encrypted, and privacy-respecting note taking app. EteSync also offers optional software as a service for $24 per year, or you can host the server yourself for free.

etebase, which is the foundation of EteSync, can also be used by other apps as a backend to store data end-to-end encrypted (E2EE).

Org-mode

Org-mode is a major mode for GNU Emacs. Org-mode is for keeping notes, maintaining TODO lists, planning projects, and authoring documents with a fast and effective plain-text system. Synchronization is possible with file synchronization tools.