SahelMesh

INSPIRATION

Communication is something we all take for granted – until it's gone. During a crisis, cellular networks are often the first to fail, leaving millions unable to call for help or coordinate rescue, even though survivors are sometimes just meters apart.

Real incidents where SahelMesh would have helped:

• 2024 Hurricane Helene (USA): Over 1,700 miles of fiber optic cables destroyed. 90% of Asheville went offline for days.
• 2023 Morocco earthquake: Cell towers collapsed within hours. Survivors trapped under rubble could not reach rescue teams only hundreds of meters away.
• 2025 Istanbul earthquake: GSM networks were paralyzed for the first 15 minutes.

These events inspired us to ask: What if the phone in your pocket didn't need a tower at all? SahelMesh is our answer.

WHAT IT DOES

SahelMesh turns every smartphone into a node of a resilient mesh network. No Internet, no SIM card required.

Key features:

• Peer-to-peer connections using WebRTC – each device gets a unique ID.
• Store-carry-forward relay – messages hop from phone to phone.
• Priority levels: DANGER, MEDICAL, HELP, URGENT, NORMAL. Critical messages go first.
• TTL (Time-To-Live): up to 10 hops, then message expires.
• Offline fallback: generate a QR code from any message; scan it on another device to inject the message into the mesh.
• Persistent storage (IndexedDB) – messages survive restarts.
• French & English – one-tap language switch.
• Network visualisation – live animated graph of connected peers.

HOW WE BUILT IT

• Frontend: React 18 (TypeScript) + Vite
• UI: Tailwind CSS + Framer Motion (glassmorphism)
• Networking: PeerJS (WebRTC signaling)
• Storage: Dexie.js / IndexedDB
• QR code: html5-qrcode
• Internationalisation: i18next
• Android APK: Capacitor
• PWA: installable on any smartphone

CHALLENGES WE RAN INTO

• WebRTC reliability: handling signaling, session negotiation, reconnects, and browser permissions was complex.
• Offline database sync: ensuring a new peer receives all missed messages without flooding the network.
• User experience: making a mesh network feel as simple as a messaging app for non-technical users.

ACCOMPLISHMENTS WE'RE PROUD OF

• A fully functional mesh network working in a browser and on mobile – no central server.
• Real-time messaging across multiple devices.
• Store-carry-forward relay with TTL and priority queuing.
• QR fallback as a last-resort communication channel.

WHAT WE LEARNED

• Peer-to-peer networking and WebRTC signaling.
• Mesh propagation trade-offs (range vs. saturation).
• Offline-first system design.
• Building for resilience, not just convenience.

WHAT'S NEXT FOR SAHELMESH

• End-to-end encryption for message privacy.
• Bluetooth Low Energy (BLE) transport – no WiFi needed.
• LoRaWAN gateway integration for rural long-range coverage.
• Advanced mesh visualisation with real-time topology map.

BUILT WITH

React, TypeScript, Vite, Tailwind CSS, Framer Motion, PeerJS, WebRTC, Dexie.js, IndexedDB, HTML5 QR Code, i18next, Capacitor, PWA

GITHUB REPOSITORY

https://github.com/Numeric02/SahelMesh

APK DOWNLOAD (ANDROID)

https://github.com/Numeric02/SahelMesh/releases/tag/v1.0.0

TEAM

Numericfirst

Built With

• capacitor
• code
• css
• dexie.js
• framer
• html5
• i18next
• indexeddb
• motion
• peerjs
• qr
• react
• tailwind
• typescript
• vite
• webrtc