Quantum-safe encrypted messenger

Q ChatPrivate. Quantum-safe. Yours.

Messages, calls and files locked on your device before they leave it. We collect nothing: no phone number, no e-mail, no contacts, no IP logs, no trackers. Just a username, and keys that never leave your hands.

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Signal protocol + PQXDHMLS groupsNo phone numberNothing logged

Q Chat chat list with contacts, a group and unread messages

An end-to-end encrypted Q Chat conversation with a photo, a voice message and a sticker

We collect nothing

Nothing to sell. Nothing to leak. Nothing to hand over.

No phone number, no e-mail, no contacts, no IP logs, no analytics. Messages and calls have quantum-safe end-to-end encryption, so the server can't read them either.

97Phone numbers
84E-mail addresses
99IP addresses logged
63Trackers & analytics

Read the privacy policy →

Inside the app

Built to feel calm. Built so we can't look.

Make it yours

Seven themes. Your colours, fonts and wallpapers.

From Quantum blue to Sakura pink, true-black Midnight or light Glacier. Every screenshot here is the real app.

All themes →

Quantum · The original: deep blue glass

A Q Chat conversation in the Quantum theme

Features

Everything you expect from a messenger. Nothing you don't want.

Quantum-safe encryption
Every message, file and call is end-to-end encrypted on your device with the Signal protocol. Only the people in the chat can read it.
Post-quantum keys
Chats start with PQXDH (ML-KEM / Kyber) and groups use a hybrid X25519 + ML-KEM suite, against harvest-now, decrypt-later.
Username only
No phone number. No e-mail. Pick a username and start. Your address book is never uploaded.
Sealed sender
Messages travel in sealed envelopes: the server delivers them without being told who sent them.
Private groups
Groups run on MLS (RFC 9420) with post-quantum keys, and every member holds the keys.
Voice & video calls
1:1 calls with keys agreed end to end and checked inside the encrypted chat. Relays only see noise.
Private notes
Send a note as a link that opens once, in any browser, then self-destructs. The key never reaches us.
Voice messages
Hold to record, slide to lock. Encrypted like everything else.
One-time media
Send a photo or video that can be opened once, then it's gone from the chat.
Stickers
Built-in sticker packs, bundled with the app: nothing is fetched from third parties.
App lock
Lock the app behind your fingerprint or your phone's screen lock, and hide its content in the app switcher.
Multi-device + Web
Link your computer with a QR code and use Q Chat Web in the browser, end-to-end encrypted.

Built so we can't look

The server is a blind courier.

Our server routes sealed envelopes and stores public keys. It never holds your private keys and never sees what you write, send or say. It keeps no logs of who connected, or from where. Even if it were stolen, there would be no messages to read.

How the encryption works →

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