A 17-year-old in Istanbul built a messaging app that works when every network fails

When mobile networks and the internet go down in a disaster, the phones in people's pockets go silent too. Emirhan Durham, a 17-year-old high school student in Istanbul, has spent since April 2025 building Crisis Connect to fill that gap. The free, open-source app swaps messages and calls over Bluetooth — the short-range radio already built into every phone — and can pass a message from phone to phone, each device acting as a relay, until it reaches the person it is meant for. It works offline with no central server, messages are encrypted, and it adds practical tools such as an SOS beacon and live location sharing. Durham, who has written about the project for a United Nations blog, is careful about its limits: it is meant for the first hours, when nearby contact matters most, not as a replacement for satellite links or official warning systems. Because people connect with family and neighbours in advance by QR code, the network is ready before it is ever needed. Crisis Connect is available free on the App Store and Google Play, and its code is public for developers anywhere to improve.

SDG 11 · Sustainable cities and communities — Mechanism: tech innovation