Just between the two of you.

Nullix is a messenger that works without a phone number or email. Messages, photos and calls are encrypted on your phone, and only the person you’re talking to can open them. Our server can’t.

Get Nullix How it works

Free · Public beta for iPhone and Android

Here’s everything our server sees.

Every message is locked on your phone before it leaves. Our server passes it along without being able to open it, and with sealed sender it can’t tell who sent it. Type something below to try it.

MLMira’s phone
Running late, save me a seat?18:52
Nullix serverwhat arrives
to
NLX-7Q4M-K2PD-9XRA
from
sealed
size
272 bytes
time
18:52:07
body
c4 1f 9e 07 5a d2 33 b8 e1 6c 0f 92 4b a7 d5 18 7e 21 c9 f4 63 0a 8d 5e b2 47 f0 19 aa 3c 86 de 52 7b e9 04 c1 9f 38 6d 2a b5 f7 11 84 e3 4c 9a 06 d8 75 2f bb 61 0e c3 98 47 a1 5d 3e f2 87 1b …
JRJonah’s phone
Running late, save me a seat?18:52

Opened with a key that exists only on Jonah’s phone.

This demo really encrypts your text in your browser, with AES-256-GCM and a throwaway key, and pads it the way Nullix does. Nothing you type leaves this page.

What the server sees

  • Who an envelope is forThe recipient’s anonymous ID. Not a name, number or email.
  • When it arrived, and its rounded-up sizeMessages are padded to fixed sizes, so the length says nothing.
  • Your IP address while you’re connectedLike any internet service. Connect through a proxy and we see the proxy’s address instead.
  • A push tokenUsed to wake your phone for a new message. Notifications carry no text.

What it never sees

  • Your messages, photos, files and voiceThey’re encrypted on your phone and opened only on theirs.
  • Who sent a messageWith sealed sender, the sender is hidden inside the encryption.
  • Your phone number, email or contactsWe never ask for them, so there is nothing to leak.
  • Your callsVoice and video are encrypted between the two phones.

We keep no connection history, and each envelope is deleted once it’s delivered. Sealed sender is used between contacts on current versions of the app.

Your account starts with a key.

When you open Nullix for the first time, your phone creates a pair of encryption keys. Your Nullix ID is a short fingerprint of the public one. There’s nothing to fill in: no number, no email, no address book.

Found only when you want to be
Share your ID or a QR code, or set a username so friends can search for you. You can remove it at any time.
Twelve words bring it back
Your recovery phrase restores the account on a new phone. Only you have it. We don’t keep a copy.
Your chats in one encrypted file
A backup holds your contacts and history, and opens only with your recovery phrase.

Your Nullix ID

NLX-7Q4M-K2PD-9XRA

An example made in your browser just now, the same way the app does it on your phone. Nothing was sent anywhere.

new key → SHA-256 → 12 characters

A full messenger, encrypted end to end.

Every chat is private by default. There’s no special secret mode to remember to turn on.

Voice messages you can read

On iPhone, a voice message can be turned into text on the phone itself. The audio is never sent off to be transcribed.

0:06
Transcribed on this iPhoneCan you bring a charger? Mine just died.

Disappearing messages

Choose 1 hour, 24 hours or 7 days, and new messages vanish for both of you.

Messages disappear after 24 h
1 hour24 hours7 daysOff

View once

A photo or video that opens once and is then erased. It can’t be forwarded or saved.

Polls and mentions

Settle plans in a group. An @mention reaches you even when the chat is muted.

Dinner on Friday?Poll · single answer · 8 votes
Thai place5
Pizza at Leo’s2
Cook at home1

Translation on the phone

Messages are translated on your device. The text isn’t sent to us, to Apple or to Google.

¿Llegas a las ocho?20:14
Translated · SpanishAre you arriving at eight?

Voice and video calls

One to one or with up to 8 people, encrypted end to end. Picture-in-picture and call waiting included.

Photos without hidden details

Location, camera model and date are stripped from photos and videos before they leave your phone.

GPS 38.7139, −9.1394Removed
Camera, lens, serial numberRemoved
Date and time takenRemoved

Send later

The message is encrypted right away and delivered at the time you pick, even if your phone is off by then.

In an hour19:52
Tomorrow morning09:00
In a weekMon

Folders and hidden chats

Sort chats into your own tabs. Keep private ones out of the list, behind Face ID or your passcode.

AllWorkFamilyHidden

Saved Messages

A private place for notes, links and files. It stays on your phone and is never sent anywhere.

Gate code for Friday: 441709:12
Lease agreement.pdf1.2 MB

Also in Nullix

  • Group chats
  • Video messages
  • Replies and forwarding
  • Edit and delete for everyone
  • Reactions
  • Read receipts you can turn off
  • Location sharing
  • QR codes
  • Chat wallpapers
  • Light and dark themes
  • 10 interface languages
  • Encrypted backups

If someone makes you unlock it.

Lock Nullix with a passcode or Face ID. A second, duress password opens an empty app or erases it, and looks exactly like the real thing.

Opens as usual

Your passcode or Face ID opens your chats.

Maximum protection
Your keys are locked with your passcode and the phone’s security chip. A full copy of the phone’s memory is useless without the code.
Erase after wrong attempts
After 3, 5 or 10 wrong passcodes, Nullix deletes its data from the phone.
Block screenshots
Keeps your chats out of screenshots and screen recordings.
Quiet notifications
By default a notification only says that something arrived, never what.

Strangers can’t just walk in.

Without a phone number, nobody finds you by accident. When someone new writes, you see a request first and decide whether to let them in.

Message requests

Someone new arrives as a request. Their files stay closed, and they won’t see that you’ve read anything until you accept.

Who can reach you

Everyone, only your contacts, or nobody. Our server enforces your choice, so a call you don’t allow never rings.

Your IP stays out of calls
Calls with people you haven’t accepted go through a relay, so they never learn your IP address.
Reports come with proof
A report can include the last messages that person sent you. Since we can’t read chats, it’s the only way to check abuse.
Show only what you want
Online status, typing and read receipts can each be turned off.

Built for networks that block messengers.

If Nullix is blocked where you are, the app looks for another way in by itself. If that’s blocked too, a friend can send you a proxy as a link.

  1. It finds a way by itself

    Nullix keeps a list of backup entries and switches to one when the direct route fails. The intermediary only sees an encrypted stream.

  2. The list can’t be faked

    The list of entries is signed by Nullix, and the app rejects any list that isn’t.

  3. Proxies travel as links

    Anyone can run a proxy and share it as a link like nullix.chat/p#relay.example.org. Open it and tap Connect.

Under the hood.

Encryption is where Nullix starts, not where it stops. Open any layer to see what protects it.

MessagesPost-quantum keys, sealed sender, hidden length, safety numbers 8
End-to-end encryption
Every message, photo, voice note and call is encrypted with the Signal Protocol, and the keys change with every message.
Post-quantum keys
New conversations add a Kyber key exchange, so what you send today stays private against future quantum computers.
Sealed sender without a middleman
Each sender signs their own certificate with their Nullix key, and the recipient checks it directly. No central service hands out identities.
An anonymous delivery line
Sealed messages travel over a separate connection that isn’t signed in. The server refuses them on a signed-in one, so a slip can’t reveal you.
Hidden message length
Messages are padded to fixed sizes before they’re encrypted, so their length says nothing.
Safety numbers
Compare a number or a pattern with your contact to make sure nobody sits in the middle.
Message requests
Someone new gets no profile, no read receipts and no open files until you accept.
Gone after delivery
The server holds an envelope only until it’s delivered, then deletes it.
On your phoneMaximum protection, duress password, remote erase, hidden chats 12
Encrypted storage
Chats live in an encrypted database, and the keys sit in the iOS Keychain or Android Keystore.
Maximum protection
Your passcode is stretched 600,000 times and combined with a secret from the phone’s security chip. Keys leave memory when you leave the app.
A password, if you want one
With Maximum protection you can use a full password instead of six digits.
Duress password
A second code that opens an empty session or erases everything, and looks just like unlocking.
Erase after wrong attempts
After 3, 5 or 10 wrong passcodes, Nullix deletes its data.
Remote erase
If your phone is lost, support can send it a signed erase command. The signing key never touches our server.
Hidden chats
Private chats stay out of the list, behind Face ID or your passcode, and their notifications are anonymous.
Screenshot blocking
Chats stay out of screenshots and screen recordings.
Private clipboard
Copied messages stay on this device and clear themselves after 10 minutes.
Incognito keyboard
Your keyboard doesn’t learn the words you type in Nullix.
Quiet notifications
By default a notification says only that something arrived.
Encrypted backups
A backup file opens only with your 12-word recovery phrase.
Calls and mediaHidden IP, no call log, cleaned photos, translation on the phone 6
Your IP stays hidden
Calls with people you haven’t accepted always go through a relay.
Out of the phone’s call log
Nullix calls don’t appear in iPhone Recents, which syncs to iCloud, unless you turn it on.
Group calls
Up to 8 people, with every connection encrypted end to end.
Photos and videos cleaned
Location, camera details and dates are removed. If a video can’t be cleaned, it isn’t sent.
Translation and transcription on the phone
Text is translated and voice is turned into text on the device. Nothing goes to a cloud service.
Location without map services
A shared location is shown without loading maps from a third party.
ConnectionCertificate pinning, backup routes, proxies, signed updates 5
Certificate pinning
The app trusts only the certificates our server actually uses.
Backup entries
When the direct route is blocked, Nullix switches to an encrypted Noise tunnel.
A signed entry list
The list of entries is signed, and the app rejects one that isn’t.
Proxies by link
Friends can share a proxy as a link, and anyone can set one up with a single command.
Signed updates from our own server
App updates come from Nullix, not a third-party service, and the app refuses any it can’t verify.
Our serverNo record of who talks to whom, your rules enforced, nothing to hand over 5
Your rules, enforced
“Who can message me” is checked by the server, so a call you don’t allow never wakes your phone.
No record of who talks to whom
No access logs and no connection history. System logs are kept for one day.
Locked down
Services run without root, in a sandbox, each with only the access it needs.
Nothing to hand over
No message content, phone numbers, emails or contact lists are ever stored.
Abuse handled with evidence
A report carries only the messages you choose to forward, and a ban takes effect at once.

Check it on your own phone

Nullix has a built-in encryption check. It runs nine tests on your phone with throwaway keys and never touches yours.

ProfileSecurity & privacyDiagnosticsEncryption check

Read the security overview

  • Two participants generated distinct keys
  • Message encrypted; plaintext absent from ciphertext
  • A foreign key cannot decrypt the message
  • Tampered ciphertext detected and rejected
  • Server tunnel: encryption matches the Noise standard
  • New core and sealed sender: the server can’t see who a message is from
  • All checks passed

Questions

Do I need a phone number or email?

No. Your account is created from encryption keys on your phone. People find you by your Nullix ID, a QR code, or a username if you choose to set one.

Can Nullix read my messages?

No. Messages, photos, files, voice messages and calls are encrypted on your phone and can only be decrypted on the phones of the people you’re talking to. Our server passes sealed envelopes along and has no keys to open them.

What does the server know about me?

Only what it needs to deliver messages: the anonymous ID an envelope is addressed to, its size and time, a push token to wake your phone, and your IP address while you’re connected. With sealed sender it doesn’t learn who sent a message, and it keeps no connection history.

What happens if I lose my phone?

Your 12-word recovery phrase brings your account back on a new phone. Your chats come back from an encrypted backup file, if you made one.

We keep no copies of either. Without the phrase, nobody can restore your account, including us.

What if someone forces me to unlock the app?

Set up a duress password in Security & privacy. Entering it on the lock screen either opens an empty session with no chats or quietly erases everything, whichever you chose. It looks exactly like unlocking with your real passcode.

Does Nullix work where messengers are blocked?

Often, yes. The app finds backup entries by itself, and friends can share proxies with you as links. No method works on every network, but the connection stays encrypted either way.

Is Nullix free?

Basic messaging is free. Some advanced features may become part of a subscription later, but privacy and encryption are free for everyone.

What protects me besides encryption?

A lot. A duress password and Maximum protection guard the phone itself. Sealed sender hides who wrote to you, padding hides how long a message is, and photos lose their location before they’re sent. Calls with strangers hide your IP, and backup entries and proxies keep you connected when Nullix is blocked.

The full list is under Under the hood.

Which phones does it run on?

iPhone with iOS 16.4 or later, and Android phones. For now, each account lives on one phone.

Join the beta.

Nullix is in public beta for iPhone and Android. Request an invite and we’ll reply with a link to install it.

iPhone

Installed through Apple’s TestFlight. Requires iOS 16.4 or later.

Request an invite

Android

Installed directly from us, with a checksum so you can verify the file.

Request an invite

Basic messaging is free, and privacy and encryption are free for everyone.