No Wi-Fi · No cell service · No tower

When the network dies, the crew doesn't.

CrewOK keeps people reachable in the first hours after an earthquake — over Bluetooth mesh, with no tower and no internet.

Watch the demo

Runs on iOS Android

The CrewOK home screen, showing the user's area and buttons for I'm safe, I need help, and Help me without internet.

Offline mesh messaging
Safe check-in
Rescue beacon

72h

The window in which most survivors are pulled out alive.

Bars of signal needed. The mesh runs entirely device-to-device.

48%

Of live rescues in the 1999 Marmara earthquake were done by neighbours.

No tower.
No internet.
Still connected.

Phones in range find each other over Bluetooth LE and pass messages along, hop by hop. No account, no server, no infrastructure. When the cell network is gone, the crowd becomes the network.

REACH

Talk without a network

Broadcast to anyone nearby over the mesh — neighbours, rescuers, strangers on the same street.

Bluetooth LE Peer-to-peer relay Works signed out

The CrewOK mesh screen: Message people nearby, tagged no internet needed and Bluetooth, with a broadcast message asking for help.

The team

Muhammad Shayan Usman

Yunus Emre Aysel

Arda Arslan

Ali Eren Ekinci

How it's built

Privacy by omission — it's the reason several database columns don't exist.

Raw coordinates are never stored — position is quantized to a ~5.5 km grid on the device.
Trusted contacts never leave the phone.
Mesh, beacon and emergency number all work signed out.

Platforms: iOS Android — one Expo codebase
Client: React Native, Expo SDK 54, expo-router, TypeScript
Mesh: Bluetooth LE, peer-to-peer relay, no server in the path
Backend: Supabase — Postgres, row-level security, Deno edge functions, pg_cron (EU/Frankfurt)
Alerts: USGS events, M4.5+, magnitude-scaled radius, 30-hour event TTL
Emergency data: 45 countries, every number carrying a source URL, access date and confidence class
Status: v1 feature-complete, prepared for App Store submission

CrewOK

Built for the moment everything else goes down.

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When the network dies, the crew doesn't.