All technologies
Offline-First Apps
Software that works without internet — encrypted local messaging, offline maps, and situational awareness tools.
Briar
Encrypted P2P messaging. No server, no internet required.
rangeBluetooth (~10m) / WiFi Direct (~100m)
bandwidthMedium
costFree
licenseNone
powerLow
Open-source encrypted messaging that works over Bluetooth, WiFi Direct, or Tor. No phone number or email required. Messages go directly between devices — no server. When internet is available, routes through Tor for anonymity.
Best for: Secure local messaging when internet is unavailable; privacy-sensitive situations
Limits: Short range (Bluetooth/WiFi Direct); phone battery is the constraint; Android only for full P2P
OsmAnd / Maps.me
Full offline maps. Pre-download before the emergency.
rangeN/A
bandwidthN/A
costFree
licenseNone
powerLow
OpenStreetMap-based offline maps with turn-by-turn navigation. Download entire country or regional map files. OsmAnd is more detailed; Maps.me is simpler. Both run fully offline.
Best for: Navigation when cellular data is unavailable; pre-downloaded regional maps
Limits: Large download size for full regions; must be downloaded before the emergency