When infrastructure fails,
Radar doesn't.
Cellular towers get congested. Power grids go down. Satellites are expensive. Underground, at sea, in the air, or in a disaster zone — Radar keeps your group connected using nothing but the devices in your pockets.
Any closed WiFi — a ship's LAN, hotel network, or in-flight WiFi — becomes a free messaging backbone. Radar discovers all peers on the same network without touching the internet.
Messages hop through intermediate devices with up to 5 relay hops, loop protection, and TTL expiry — so a message sent to someone around the corner can reach them via a third device in between.
WiFi Aware creates direct encrypted data links between devices with no router, no access point, and no internet. Bluetooth LE provides presence beaconing even when WiFi is unavailable.
Wherever you lose signal, Radar finds a way
From post-disaster rubble to the inside of an aircraft, these are the situations where standard messaging apps go silent — and Radar keeps talking.
Natural Disaster & Grid Failure
An earthquake, flood, or major civil emergency can bring down cellular towers, knock out power, and sever fibre links in minutes. When the grid goes dark and every conventional communication channel fails, Radar operates entirely from the battery in your phone. WiFi Aware creates direct encrypted links between nearby devices. The mesh relay forwards messages through other Radar users, building a communication network from nothing but the people around you.
Cruise Ship at Sea
Onboard satellite internet costs a fortune and crawls along. But the ship runs its own closed WiFi network that connects every passenger and crew member on the same LAN. Radar discovers everyone on that network via mDNS and local scanning — free messaging, radar view, and group chat, all without using a single byte of expensive satellite data.
Aircraft & In-Flight WiFi
At 35,000 feet with phones in airplane mode, standard messaging is impossible. Many modern aircraft offer in-flight WiFi as a closed local network — no external internet access. Radar operates entirely within that LAN, letting passengers message each other, share their seat location on the radar view, and coordinate free of charge. No satellite subscription required.
Metro & Underground Rail
Deep in a subway system, cellular signal disappears. But many underground networks now provide station and in-carriage WiFi — a closed local network with no internet gateway. Radar uses that WiFi to discover other passengers nearby, enabling messaging between friends separated by carriages or platforms, without ever needing the cell network or internet.
Clubs, Concerts & Packed Venues
Thousands of people in one space overwhelm local cell towers. Calls drop. Messages sit undelivered for minutes. Radar bypasses the cellular network entirely — WiFi Aware creates direct device-to-device links, while BLE continuously broadcasts your presence so friends can locate you on the radar view even in a heaving crowd. No signal, no problem.
Remote Islands & Wilderness
A tropical island with no mobile mast, a mountain expedition, a festival in a field — no towers, no internet, no problem. WiFi Aware creates peer-to-peer links directly between devices in the group, with no access point needed. BLE keeps everyone visible on the radar view. Messages relay through the group as a mesh, ensuring nobody is out of reach.
Underground Shelters & Bunkers
Reinforced concrete and underground depth block all radio signals from the outside world. Inside the structure, Radar runs purely on local WiFi and Bluetooth between the devices present. The store-and-forward mesh means messages are held and delivered the moment a relay path opens up — keeping communication alive even as people move between rooms or levels.
Civil Defence & Emergency Coordination
When professional responders need to coordinate across a building, site, or subterranean facility without relying on external infrastructure, Radar provides a self-organising communications mesh built from the team's own devices. Messages hop through intermediate team members at up to 5 relay hops, with loop prevention and automatic expiry. No base station, no repeater, no radio licence required — just Android devices and Radar.
Three technologies, zero infrastructure
Radar stacks three complementary radio technologies so that if one isn't available in your environment, another takes over — seamlessly and automatically.
WiFi Aware (NAN)
WiFi Aware lets two Android devices find each other and open an encrypted data socket directly — no router, no hotspot, no internet. This is Radar's primary messaging channel: sub-second discovery, high bandwidth, and completely peer-to-peer. Works on any Android 8.0+ device that supports the standard (most modern flagships and mid-range phones).
Isolated LAN (mDNS)
On any WiFi network — ship, hotel, aircraft, venue, office — Radar uses mDNS to announce and discover other Radar users on the same subnet, then opens direct TCP connections for messaging. The internet gateway can be down entirely or behind a paywall; Radar only needs the local network layer to work. Network scan also identifies all other devices on the LAN.
Bluetooth LE Mesh
BLE runs continuously, even in the background, advertising your presence and scanning for other Radar users. It powers the radar view with RSSI-based distance estimation, and acts as a relay transport for the mesh when WiFi isn't available. BLE is the lowest-power, longest-lived radio in your pocket.
Store-and-Forward Mesh
Messages that can't be delivered immediately are stored and forwarded the next time a path opens. Each message carries a TTL (up to 5 hops), a unique ID for duplicate prevention, and loop-protection counters. This means a message can traverse a chain of devices to reach someone out of direct range — building an ad-hoc network from the people themselves.
End-to-End Security
WiFi Aware connections use PSK-secured data paths. Relay messages are encrypted at the transport layer. In local-only mode, no data ever leaves your device or network — there is nothing to intercept at a server because there is no server in the loop.
Background Operation
A persistent foreground service keeps BLE advertising and location broadcasting active when the app is minimised. You don't need to keep the screen on — Radar continues announcing your presence and accepting relay messages silently in the background, so your group always knows you're there.