offline-communication

A curated list of open protocols, applications, hardware, and resources for communication during internet shutdowns, disasters, intermittent connectivity, censorship and off-grid operation.

Offline emergency communication for Android: Bluetooth mesh with live group radar, SOS and photos, plus an optional internet bridge. Free, open source, no accounts.

Quantum-Resistant, AI-Powered Offline Mesh Communication via WiFi & Bluetooth

Encrypted, sound-based communication app for Android and PC using GGWave protocol. Secure, offline, and air-gapped.

Research-oriented acoustic communication platform that transmits digital images through sound using Multiple Frequency Shift Keying (MFSK), enabling offline image communication for signal processing, biomedical engineering, and resilient communication research.

Android-only React Native module for peer-to-peer communication using Wi-Fi Direct. Ideal for offline messaging and file sharing.

A tool for encoding large text or files into multiple QR codes arranged in arrays, and decoding them back, ideal for offline data transfer between isolated networks.

ErikrafT Wi-Fi™｜Open-source wireless connectivity project using Wi-Fi, Wi-Fi Direct, and Mesh networking for offline communication and Internet access through compatible gateways.

Vajra is a decentralized, software-defined emergency mesh network for scenarios where cellular and Wi-Fi fail. It enables smartphones to broadcast and relay SOS signals and GPS coordinates using only Bluetooth (BLE). Features include 1-byte intent compression, high-detail offline mapping, and a 1-10m proximity alert—all on existing hardware.

An advanced, dependency-free acoustic data transceiver and kinetic transmission protocol written from scratch in pure C++17. Modulates text data into near-ultrasonic frequencies and mechanical vibrations, bypassing jammed or dead RF radio frequencies during total network blackouts.

No internet communication in times of emergencies!

No internet, no cloud, no GSM :- LoRa-based offline peer-to-peer communication system for explorers - ESP32 firmware + Flutter app.

Send a text message between two phones using only sound. No internet, WiFi, Bluetooth or pairing. Neural-codec acoustic modem in the browser.

An open source Acoustic Data Transmission Messenger which transmit text through the air using sound. No internet. No Bluetooth

Open-source numbers-station project for research, education and study: customizable number dictionaries, live minimodem FSK chat/files, microphone RX, speaker TX and audio calibration on Linux/macOS.

A simple half-duplex audio chat using GGWave, with a real-time volume meter to monitor microphone input levels. It encodes and decodes messages using sound-based data transfer.

Offline-First Peer-to-Peer Mesh Communication Platform

Offline phone-to-phone file transfer using light and sound: animated QR codes and a data-over-sound modem, no Internet, Wi-Fi or Bluetooth. Open-source Flutter app for Android, iOS and web.

Offline communication hub for disaster relief inspired-by-piratebox- Deploy chat, file sharing, and tactical mapping on DD-WRT routers

A Bluetooth Low Energy mesh messaging app for Android — no internet, no pairing, no setup needed. Currently supports direct 2-device chat; building towards multi-hop mesh relay where messages pass through intermediate devices to reach anyone in range. Built with Kotlin & Jetpack Compose.