Messaging That Works When the Cell Towers Don't
You've probably experienced this: a concert, a protest, a natural disaster, or just a remote hiking trail where your phone becomes a very expensive brick because there's no signal. What if your messages could hop from device to device instead of relying on infrastructure that might not be there? Columba is an Android app that brings messaging and voice calls to the Reticulum network, and it doesn't need the internet, cell towers, or any central servers to work.
What It Does
Columba is a native Android app (Material Design 3, if you care about that sort of thing) for the Reticulum network. It sends LXMF messages and makes LXST voice calls over mesh connections. Reticulum itself is a networking stack built for low-bandwidth, high-latency links that can run over nearly any medium, and Columba puts that in your pocket.
The app connects through several transports: Bluetooth LE for the people physically near you, WiFi for your home network, LoRa radio via RNode for longer distances, and TCP if you want to reach a Reticulum server anywhere in the world. It uses a native Android implementation of ble-reticulum to handle BLE messaging with other Android and Linux devices. On top of messaging, you get location sharing with a dedicated map view, offline map downloads and imports in MBTiles format (both vector and raster), and a browser for NomadNet pages over Reticulum networks.
Why It's Cool
It's infrastructure-independent by design. The whole point is that messages travel device to device. When the internet is down or unavailable, the app still does its job. That's a fundamentally different reliability model than any messaging app that quietly assumes a server exists somewhere.
Privacy isn't a feature toggle, it's the architecture. End-to-end encryption, no accounts, no tracking, no central servers. There's nothing to sign up for and nothing collecting your data, because there's no central anything.
Identity handling is genuinely thoughtful. You generate your messaging identity right on the device, and you can manage multiple identities and swap between them. You can export and import identities for backups or device migration, and it imports from other Reticulum clients like Sideband. There's even a built-in QR code scanner and generator for sharing your identity with others.
It plays well with the existing Reticulum ecosystem. This isn't a walled garden. The README links out to Reticulum, LXMF, LXST, RNode firmware, and Sideband, and the app connects to Reticulum servers over TCP. You're joining a network, not a platform.
Small touches that show care. You can help relay traffic for others and expand the mesh. You can rice the interface with custom color themes. The app is distributed through GitHub Releases, Obtainium, and even over NomadNet itself, which is a nice bit of dogfooding.
How to Try It
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Grab the latest APK from the Releases page and install it on your Android device. The README points to SECURITY.md for APK verification instructions, which is worth reading before you sideload anything.
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If you prefer automatic updates, install it through Obtainium using the badge link in the README.
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If you're already on the Reticulum network, you can pull the APK over NomadNet at
8d1788fdb4e9f85303cfdf7481e721c7:/page/index.mu. -
Once installed, generate your identity on-device, then start connecting. BLE is the easiest starting point if there are other Reticulum users nearby; WiFi and TCP are options if you have a local network or a server to reach.
The repository is at github.com/torlando-tech/columba. If you want background on the underlying stack, start with the Reticulum documentation.
Final Thoughts
Columba is a niche tool for a niche network, and that's fine. If you're already curious about Reticulum, this is the most convenient way to carry it in your pocket. If you've never heard of Reticulum, the app is a good excuse to learn what mesh networking can actually do when it's not abstracted behind a cloud service. Either way, it's a solid example of building a friendly front end for a technically ambitious protocol, and the fact that it ships over the very network it uses tells you the maintainers believe in what they're building.