What is Lithium?

Lithium is an end-to-end encrypted productivity app built on zero-knowledge architecture. The server never sees your data in plaintext — everything is encrypted on your device before it’s synced.

Key Principles

Zero-knowledge encryption — Your password never leaves your device. A master key is derived locally using Argon2id, and all content is encrypted with XChaCha20-Poly1305 before syncing.

Local-first — The app works offline. Your data lives in IndexedDB on your device and syncs to the server when you’re connected. Edits are instant, never waiting on the network.

Block-based editor — Content is organized as a tree of blocks inside pages. Blocks can be paragraphs, todos, headings, events, or voice notes. Nest them, reorder them, collapse them.

Who is it for?

If you don’t want your notes, todos, and plans to be one security breach away from being public — Lithium is the alternative. Your data is encrypted before it ever leaves your device. Even we can’t read it.