Privacy is not optional
The messenger that works without internet. End-to-end encryption, mesh networking, and no phone number required.
Better calls, encrypted groups and a desktop app — available now on Android, Windows and Linux. Coming to iPhone and Mac with the next update.
Download a region, find what you need, and navigate without handing your location history to an ad network.
Voice calls now use the Opus codec, compiled by us from its source code. Calls connect directly peer-to-peer when they can, and through our secured relay when they can't.
ANDROID · DESKTOPFaster recovery when frames are lost and a bitrate that adapts to your connection, for steadier video on weak networks.
ANDROID · DESKTOPEvery group message is encrypted end to end for each member, and group chats open on the latest message.
ANDROID · DESKTOPOne notification per message, showing only the contact or group name — the message text stays hidden unless you turn previews on.
ANDROID · DESKTOPThe maps app you pick now opens every shared place, address and check-in.
ANDROIDDesktop 1.2.0 brings encrypted chats, groups and calls to your computer. It uses the internet and our relay — the offline mesh stays on your phone.
WINDOWS · LINUX12 privacy features including offline maps, on-device AI, encrypted voice and video calls, and mesh networking — all designed with your security as the top priority
AES-256-GCM authenticated encryption with the Double Ratchet protocol. Only you and your recipient can read messages.
Connect directly with nearby devices via Bluetooth and WiFi. No internet required for local communication.
End-to-end encrypted voice and video calls with Opus audio and video that adapts to your connection. Direct peer-to-peer when possible, via our secured relay when not.
There is no account and no phone number, and mesh messages never reach a server. When a message does go through our relay, it sees the sender and recipient public keys, the time and the size — never the contents.
Set messages to auto-delete after reading. Leave no trace of sensitive conversations.
Messages go peer-to-peer over Bluetooth and WiFi with no server involved at all. Only when no peer is reachable do they fall back to our own encrypted relay, optionally over Tor.
Smart corrections, translations, tone reformulation, and AI assistant — all 100% offline using Apple Foundation Models.
Create Telegram-like bots with Python. Automate messages in channels and groups with a simple API.
Optional on iOS and Android: your already-encrypted relay traffic is wrapped as ordinary-looking web requests with padded sizes. Helps against simple filtering — not a guarantee against a determined censor.
Download regions for offline use. Turn-by-turn navigation for walking, driving, cycling. Search streets and POIs — no internet needed.
View images fullscreen with pinch-to-zoom in group chats. Swipe to browse all shared photos in the conversation.
Get OSHI on Google Play, or download the APK directly if you'd rather not use the Play Store.
Powerful language AI that runs 100% on your device. No data ever leaves your phone.
AI-powered spelling and grammar correction in any language. Context-aware, not just dictionary lookup.
Rewrite your message in 6 tones: Formal, Casual, Friendly, Professional, Playful, Persuasive.
Translate messages to 16+ languages. Translate received messages with one tap.
Ask questions directly in the chat. Get instant answers without leaving the conversation.
Mesh first, encrypted relay when no peer is near — with an optional Tor layer
Direct device-to-device. No server is involved at all.
When no peer is in range, we carry the message on our own server
Optional layer that hides your IP from the relay
From a protest to a mountain trail, OSHI keeps you connected when ordinary messengers can’t.
On filtered networks, an optional setting makes OSHI's traffic to its relay look like everyday web requests. It's an extra layer on top of encryption — not an invisibility cloak.
Each request to our relay is sent as a routine page-view or screen-view event to one of several generic addresses, instead of a recognisable messenger API call.
Requests are padded to a few fixed sizes, from 4 KB up to 4 MB, so an observer can't read the exact length of what you send.
The wrapper only changes how traffic looks. Your messages remain end-to-end encrypted and signed — the relay still can't read them.
If a disguised request fails, OSHI retries it the same way. It never quietly switches back to the normal, recognisable connection.
When the network is down or fully blocked, nearby phones exchange messages directly over Bluetooth and Wi-Fi, with no server at all.
Off by default on iOS and Android — switch it on in Settings. The desktop app for Windows and Linux doesn't include it.
Built in Switzerland under strict Swiss privacy law, OSHI uses the same encryption protocols trusted by security experts worldwide. Your data is protected at every step.
On iOS 26 and macOS 26, and only when both people in a conversation are running a version that supports it, OSHI negotiates X-Wing — ML-KEM-768 combined with X25519 — for the key exchange. The app ships with a deployment target of iOS 17.5, so older devices keep the classical X25519 exchange; the upgrade is negotiated per conversation and happens silently once both ends can.
The reason to care is harvest-now-decrypt-later: an adversary who can record traffic today can simply store it and wait for a quantum computer capable of breaking X25519. Anything captured now would then become readable retroactively. A key exchange that already resists quantum attack is the only thing that protects a conversation you are having today against a machine that does not exist yet.
It is deliberately hybrid and never post-quantum alone. The shared secret depends on both the ML-KEM-768 and the X25519 halves, so a future break of ML-KEM cannot make a session weaker than it would have been with X25519 on its own. If the hybrid exchange cannot be completed, it fails closed rather than quietly falling back to something weaker.
Implementation: OSHI/PostQuantumKEM.swift, using CryptoKit's XWingMLKEM768X25519 under a .hybridWhenAvailable policy. Open source and auditable like the rest of the app.
OSHI's privacy and anti-censorship features are designed to protect freedom of expression and personal safety in regions where basic human rights are at risk. These tools are intended for journalists, human rights activists, political dissidents, and civilians in conflict zones.
Use of these features is subject to the laws of your jurisdiction. Users are solely responsible for ensuring compliance with local regulations.
Learn more about what makes OSHI the most complete private messenger
Send encrypted messages without internet via Bluetooth and WiFi Direct. Works offline, no cell service needed.
Read full guide →Optional mode that makes your encrypted relay traffic look like ordinary web requests on filtered networks — with its limits stated plainly.
Read full guide →Translation, smart replies, and AI assistant powered by Apple Foundation Models. 100% offline, zero cloud data.
Read full guide →Join thousands of users who trust OSHI for their private communications.
