mBLEChat

No signal? No SIM? No problem.

mBLEChat lets nearby phones message each other over Bluetooth, with no internet, no mobile network and no servers. If the person you're messaging is out of range, other mBLEChat phones nearby pass the message along until it arrives.

WORKS WHERE NETWORKS DON'T
• Mines, tunnels and basements
• Floods, storms and network outages
• Treks, mountains, forests and camping
• Crowded festivals and stadiums where networks jam
• Flights, ships and remote areas

MESSAGES HOP PHONE TO PHONE
Every phone running mBLEChat also works as a relay. Messages are stored and forwarded until the recipient comes back into range, and a delivery tick confirms they arrived.

PRIVATE BY DESIGN
• End-to-end encrypted with ECDH P-256 key exchange and AES-GCM
• Phones that relay your message can't read it
• Delivery ticks are authenticated, so they can't be faked
• No account, phone number or email needed

YOUR DATA STAYS ON YOUR PHONE
mBLEChat has no servers and doesn't use the internet. Messages are stored only on the phones in the conversation, and you can delete old messages at any time.

SIMPLE TO SET UP
Open the app and nearby devices appear automatically. One setup screen checks Bluetooth, permissions and background settings, and helps you fix anything that would stop messages being delivered.

WORKS IN THE BACKGROUND
mBLEChat keeps finding nearby phones and relaying messages with the screen off, so messages reach you even when the app is closed.

WHY THESE PERMISSIONS?
• Nearby devices (Bluetooth): to find and connect to other mBLEChat phones
• Location (Android 11 and older only): Android requires it for Bluetooth scanning. mBLEChat never reads or stores your location.
• Notifications: to tell you when a message arrives
• Battery optimisation exemption (optional): so relaying keeps working in the background

PLEASE NOTE
Bluetooth range is typically tens of metres between two phones, and messages travel further when more phones are nearby to relay them. mBLEChat is not an emergency service and should not be your only way to call for help.