Messaging without servers. Even without internet.

There is no central service where you have an account and through which your chats flow. Messages go directly from device to device or are passed along by other MeshUp devices.

There are two helpers, both optional: a mesh node connects devices over the internet when they can’t find each other directly – it only relays encrypted tunnels. And a push service wakes sleeping devices with an empty message. Both can be switched off.

Yes, as long as the devices can reach each other: on the same Wi-Fi network – even one without internet access – or within Bluetooth range. If your contact is further away, other MeshUp devices can carry the message and pass it on.

Text, photos and voice messages travel in passed-along envelopes. Calls, the walkie-talkie and large files need a connection between both devices, either direct or via a mesh node.

No. On first launch MeshUp creates a key pair on your phone – that is your identity. You add contacts by QR code, NFC or invite link.

If you want, you can link a phone number or email address so friends can find you from their address book. The mesh node only receives Argon2id hashes.

All connections use the Noise protocol with X25519, ChaCha20-Poly1305 and SHA-256; the implementation is checked against official test vectors. Every message travels in its own envelope with a fresh key that only the recipient can open.

MeshUp does not use a Double Ratchet that keeps renewing keys. If your private key is stolen, recorded messages sent to it can be read. Verify new contacts by their safety number or in person with a QR code.

Yes. MeshUp doesn’t need Google Play services: location comes straight from Android, maps from OpenStreetMap, wake-ups via UnifiedPush – for example with the ntfy app.

Firebase Cloud Messaging is merely an optional alternative for devices with Google Play services or microG. Without any push at all, MeshUp keeps the connection open with a foreground service.

A mesh node is a small relay on the internet. It brings together devices that can’t reach each other over Wi-Fi or Bluetooth and passes the encrypted data stream through. It doesn’t store messages.

You don’t have to run one: the app comes set up with mesh-node1.3xd.eu. If you like, start your own (Node.js, no dependencies) and add it in the app – or use fixed addresses over a VPN, Tailscale or WireGuard.

No. MeshUp is available for Android 10 and later, and as a desktop client for Linux and Windows. There’s no ready-made macOS package, but the desktop client can be built from source on a Mac.

The Android app checks for a newer nightly at most every six hours, downloads it when you tap, verifies checksum and signature and then lets Android install it. Your chats and settings are kept. The desktop versions update themselves.

Since no server keeps your data, backups matter: MeshUp saves keys, contacts, chats and media into an encrypted file, manually or automatically every day or week. With it, you can restore everything on a new phone. Without the backup password the file can’t be opened – there is no back door.

Nothing – for any non-commercial use. The download is free, and MeshUp contains no ads and no analytics trackers. If you’d like to use MeshUp commercially, please get in touch first using the details in the legal notice.

MeshUp is source-available: the complete source code of the app, the desktop client and the mesh node is public, and anyone can read, review, modify and build it. It is licensed under the PolyForm Noncommercial License 1.0.0. Because that licence excludes commercial use, it is not an open-source licence as defined by the Open Source Initiative.

Any non-commercial use is allowed: personal use, research and teaching, and explicitly use by charitable organisations, schools and other educational institutions, and government bodies. Commercial use is available on request.