Notesnook

Notesnook is a free and open-source note-taking app positioned as an end-to-end encrypted alternative to Evernote. It focuses on user privacy and ease of use, with zero knowledge principles so notes are encrypted on your device before leaving it.

Encryption uses XChaCha20-Poly1305 and Argon2, with the cryptography layer wrapping libsodium. Notesnook ships web, desktop, and mobile clients built with React, React Native, and Electron, plus a web clipper for saving pages straight into your notes. An importer brings your existing notes across from other apps.

Notesnook is fully open source under the GPLv3 license, so anyone can build the clients from source and inspect how encryption works. Encryption claims can be checked independently through Vericrypt, an external verification tool. Because notes are encrypted on the device, the service never sees their contents.