Zerion

Zerion is a private messenger. It runs over Tor, so your IP address stays hidden from the people you talk to and from the network itself. There's no phone number, no email, and no account on anyone's server. Your data lives encrypted on your own device, nowhere else.

Everything is end-to-end encrypted with hybrid post-quantum cryptography: today's proven algorithms together with the new NIST quantum-resistant ones. Keys move forward with every message, so a key uncovered today cannot open yesterday's conversations. If large quantum computers arrive sooner than expected, what you sent in the past stays protected.


WHAT YOU CAN DO

• One-to-one chats, end-to-end encrypted
• Group chats up to a few dozen people
• Voice calls over Tor, on by default, plus opt-in beta video calling
• Send photos, videos, voice notes, and documents
• Disappearing messages, with an optional default timer for new chats
• Stickers
• Introduce two of your contacts to each other, securely
• A built-in vault for passwords, notes, and private files, with search and sort
• Back up your account to an encrypted file, or move it to a new phone over Tor
• Channels, a one-to-many broadcast layer with optional discussion threads
• Translated into more than 35 languages


CHANNELS

One person writes, many people read.

• Public channels: anyone with the invite link can subscribe
• Private channels: people ask to join and the owner approves
• Discussion threads: the owner decides, per channel, whether subscribers can reply
• Reactions, pinned posts, and attachments
• Editor delegations: let trusted people post without sharing your identity key
• Mute notifications for any channel
• Subscribers never see one another, so no member list leaks between them


HARDENED MODE (OPT-IN)

Three independent protections under Security settings, all off by default:

• Refuse to start on tampered devices (unlocked bootloader, modified system)
• Refuse to start when a debugger, root, or hooking framework is detected
• Sign out automatically, or wipe, if USB debugging or file transfer is switched on


PRIVACY AND SECURITY

• Tor-only transport. No Wi-Fi, Bluetooth, or LAN exposure
• No phone number, no email, no central server
• No telemetry, no analytics, no crash reporting
• No logging of any kind, verified at build time
• Encrypted at rest with SQLCipher and a key derived from your password
• Screenshots blocked inside the app
• Notifications never reveal message contents
• The clipboard auto-clears after you copy something sensitive
• Fully open source, GPL v3, security-reviewed before each release


UNDER THE HOOD

• Hybrid post-quantum key exchange (X25519 + ML-KEM-768)
• Hybrid signatures (Ed25519 + ML-DSA)
• Forward-secret message ratcheting
• Calls encrypted with AES-256-GCM; storage with SQLCipher (AES-256)


SUPPORT THE PROJECT

Zerion is free and open source, with no ads, no trackers, and no investors. If you'd like to help keep it independent, you can donate:
https://zerion.chat/donate.html


WHO IT'S FOR

People who want to talk to other people without a third party in the middle. Journalists and their sources, activists, lawyers and their clients, people in countries that block secure messengers. Anyone who doesn't want to hand a phone number to a tech company every time they install a messenger.


WHAT IT WON'T DO

• It won't message people who aren't on Zerion
• It won't work without an internet connection (Tor needs one)
• It won't restore your account if you forget the password. There is no recovery, and that's the point


LEARN MORE

• Website: https://zerion.chat
• Source: https://github.com/zerionproject/Zerion

GPL v3.

Is Zerion free to download?
Yes. The APK file linked from this page is free. The developer may offer in-app purchases once installed, but obtaining the installer itself costs nothing.

What Android version does Zerion require?
Android 4.1+ or newer. Installing on older devices may cause crashes or refuse to install.

Is Zerion safe to install?
We link to the exact APK published by F-Droid Open Source. We do not modify the file. Still, as with any sideloaded app, scan it with a reputable antivirus before opening it, and only grant permissions the app genuinely needs.

How do I update Zerion?
Install the newer version on top of the old one — Android will keep your data. If the signature differs, uninstall first (you may lose local progress).

Why is the app not installing?
Common causes: not enough storage, an older Android version than 4.1+, or a conflicting build already installed. Free up space, check your OS version, and uninstall any previous copy before retrying.

1. Tap the Download APK button above and save the file to your device.
2. Open your device Settings → Security (or Apps → Special access → Install unknown apps) and allow your file manager or browser to install unknown apps for this one file only.
3. Open the downloaded com.professor.zerion.apk file from your Downloads folder.
4. Tap Install and wait for Android to finish.
5. Open «Zerion» by F-Droid Open Source and grant only the permissions it actually needs.
6. Revoke the "unknown sources" permission once you are done installing.

Note: this page hosts or links to the installer only. The application name, icon and description are provided for identification. All trademarks belong to their respective owners.