notesnook

Notesnook is an open-source note-taking app positioned as a privacy-focused alternative to Evernote. All notes are encrypted on your device before they leave it, using two specific encryption algorithms (XChaCha20-Poly1305 and Argon2), so the service itself never sees your note content. This approach is sometimes called zero-knowledge encryption.

The app is available across web browsers, Windows, Mac, and Linux desktops, and Android and iOS phones. A browser extension called the web clipper lets you save content from any web page directly into your notes. All clients share the same core codebase and sync through the same backend.

The technical stack is TypeScript and JavaScript throughout, with React powering the web and desktop interfaces, React Native handling the mobile apps, and Electron wrapping the desktop version. Everything lives in a single repository with separate packages for the editor, cryptography layer, core sync logic, theme, and logging.

The cryptography package is a wrapper around libsodium, a widely audited encryption library. If you want to independently verify that the encryption works as described, the project links to a tool called Vericrypt where you can check those claims yourself without trusting the developers.

To use the app, you visit the website and create a free account with an email address. The README links to a blog post explaining why email is required. You can import existing notes from other apps using a separate Importer tool. Support is available via Discord, email, Twitter, or by filing a GitHub issue. Contributing guidelines are included in the repository for anyone who wants to help build it.