Notesnook

Notesnook is an open source, zero-knowledge private note-taking app for individuals who want to write, organize, and sync notes across Web, Android, iOS, and Desktop without exposing their data.

Key capabilities include:

• End-to-end encrypted syncing across devices, with encryption applied before data leaves the device
• Rich text editing with full formatting plus tables, task lists, outlines, code blocks, math/formulas, embeds, and Markdown support
• Attachments and uploads, including file and image uploads (Free plan includes 50MB/month uploads; higher monthly limits on paid plans)
• Vaults and app lock for protecting sensitive notes, plus export options available on the free plan

Pricing: Freemium. Essential $1.99/mo or $19.99/yr (1GB/month uploads), Pro $6.99/mo or $69.99/yr (10GB/month uploads, unlocks everything), Believer $8.99/mo or $89.99/yr (25GB/month uploads), Education $9.99/yr; 14-day money-back guarantee.

What makes it notable: it focuses on privacy by design (zero-knowledge encryption, no tracking claims) and is fully open source, including client apps and a self-hostable sync server, positioning it as a privacy-focused alternative to services like Evernote.