OSHI Messenger: Offline Chat

OSHI Mesh is an encrypted chat app that works offline — over Bluetooth, Wi-Fi mesh and LoRa radio when there is no internet.

Most messengers stop at "no signal". OSHI keeps going: it hands your message to whatever path exists — the internet when you have it, a direct Bluetooth or Wi-Fi link to someone nearby when you don't, and a long-range LoRa radio when nobody is nearby at all.

Every message is end-to-end encrypted on your phone before it leaves, whichever path it takes.


WORKS WITHOUT INTERNET

• Bluetooth and Wi-Fi mesh chat — message people around you with no router, no SIM and no mobile data: at a festival, on a plane, in the mountains, during an outage.
• LoRa radio mesh (Meshtastic) — pair a low-cost LoRa radio over Bluetooth and reach kilometres of open ground with no infrastructure at all.
• Messages hop from phone to phone through the mesh, so a friend out of range can still be reached through someone in between.
• When the internet comes back, everything queued goes out automatically.


PRIVATE BY DESIGN

• End-to-end encryption on every path, built on X25519 key agreement and AES-256-GCM. Internet chats use an X3DH + Double Ratchet session.
• No phone number, no email, no account to create. Your identity is a key pair generated on your device.
• Screenshot protection, biometric lock, view-once media and a real "delete for everyone".
• Honest about limits — the app tells you when it cannot send, and why.


ENCRYPTED VOICE AND VIDEO CALLS

• Voice and video calls, encrypted end to end.
• Voice uses the Opus codec, compiled by us from its published source code — never a system codec.


EVERYTHING YOU EXPECT FROM A MESSENGER

• Text, photos, videos, documents, voice notes and GIFs
• Group chats with admin controls, polls and shared media
• Replies, reactions, edits, forwarding and pinned messages
• Scheduled messages and scheduled calls
• Live location sharing
• Safety check-in: set a destination and a deadline, and OSHI alerts a contact if you do not arrive
• 34 languages


OFFLINE MAPS

Download the map of your region in advance — more than 100 countries are available — and use it with no connection at all, with points of interest.


ON-DEVICE AI ASSISTANT

An AI assistant that runs entirely on your phone: Gemini Nano on phones that support it, or an offline model you download once. Your questions never leave the device.


TALKS TO IPHONES

OSHI on Android and OSHI on iPhone are the same network. Messages, media, calls, groups and the mesh work across both.


WHO IT IS FOR

Hikers, sailors and pilots out of coverage. Journalists and their sources. Festival crowds where the cell towers are saturated. Anyone in a blackout, a natural disaster, or a place where the network is watched or shut off. And anyone who would simply rather their messages were nobody else's business.


HONEST ABOUT WHAT IT COSTS

Bluetooth and Wi-Fi mesh need nothing but the phones — but the person you write to must have OSHI too, and be within range or reachable through other OSHI phones. LoRa needs a compatible radio you buy separately. Range depends on terrain: expect a few hundred metres in a city and considerably more with height and open ground. The app never invents a number it cannot measure.