UltimaOS — A private, post-quantum encrypted personal workspace

uOS is a complete personal workspace running entirely in your browser. Chat, mail, files, notes, documents, kanban boards, and more — all locked so well that not even we can read your things.

What is UltimaOS?

UltimaOS (uOS) is a web-based personal operating system focused on privacy. Every message, file, note, and document you store is end-to-end encrypted in your browser using post-quantum cryptography. Your private keys never leave your device — not even our servers can decrypt your data.

Apps included

uChat — End-to-end encrypted messaging with markdown, voice notes, and attachments.
uMail — Private email with encrypted storage.
uFiles — Encrypted file storage with secure sharing.
uNotes — Private notes and rich-text documents.
uBoards — Kanban-style task boards for personal and team projects.
uAI — Bring your own AI assistant (OpenAI, Anthropic, local models) — your conversations stay encrypted.
uStudio — Build and publish your own websites and mini-apps.
uBrowse — Browse published websites inside uOS.

Cryptography

uOS uses 100% post-quantum cryptography — there is zero classical asymmetric crypto in the codebase:

ML-DSA-65 (FIPS 204) for digital signatures (1952-byte public keys).
ML-KEM-768 (FIPS 203) for key encapsulation (1184-byte public keys).
XChaCha20-Poly1305 for symmetric authenticated encryption.
HKDF-SHA256 for domain-separated key derivation.
Argon2id for any password-like material.

Privacy guarantees

No cookies. No tracking. No third-party analytics on app surfaces.
No central password database — your identity is derived from a 3-field login (name, phrase, email) directly in the browser.
Private keys never leave your device. They are derived deterministically and held only in browser memory.
Server only sees public keys and encrypted blobs.
Hosted in the European Union. GDPR compliant.
Invite-only access (closed beta).

For organizations

uOS for Business deploys an isolated, end-to-end encrypted workspace for your organization in minutes. Bring-your-own AI, no password database, GDPR compliant, built in the EU. Learn more at https://uos.sh/business/.

Try it

uOS is in early access and free while we build it together. Try the public demo at https://uos.sh/demo/ or request an invite from https://uos.sh/.