Sonar

Sense who's nearby before you see them.

Sonar is a decentralized, privacy-first messenger and Lightning wallet. It speaks two transports — a local Bluetooth LE mesh for offline, proximity communication and the internet-based Nostr protocol for global reach — and adds end-to-end-encrypted group messaging (Marmot / MLS over Nostr), nearby Bluetooth payments, and peer-to-peer voice/video calls on top. No accounts, no phone numbers, no central servers — your identity is a key you hold.

Sonar grew out of bitchat and keeps its mesh + Nostr foundation, then rebuilds the product around a single shared Rust core that drives native iOS/macOS and Compose Multiplatform (Android/Desktop) apps.

License

This project is released into the public domain. See the LICENSE file for details.

Features

• Dual transport — Bluetooth LE mesh for offline, Nostr for internet-based messaging, with automatic transport selection (Bluetooth → Nostr fallback → smart queueing).
• White Noise secure DMs — end-to-end-encrypted group messaging via Marmot (MLS over Nostr); interoperable with the White Noise client in both directions.
• Encrypted media — image / file / voice sharing over the Marmot media module (MIP-04).
• ⚡ Lightning wallet — an embedded wallet (Breez SDK Liquid; BOLT12 / BIP-353 capable) tied to the same identity, so the same key restores the same wallet.
• Nearby payments over BLE — bidirectional, payments-only Lightning over Bluetooth (⚡PAY), no chat required.
• Voice & video calls — peer-to-peer ☎CALL over an iroh QUIC transport (NodeId-authenticated, NAT hole-punching).
• Location channels — geographic chat rooms addressed by geohash, with live presence, over global Nostr relays.
• Tor by default — all internet traffic is routed through a local Tor SOCKS5 proxy, fail-closed when Tor isn't ready.
• Privacy first — no accounts, no phone numbers, no persistent identifiers; mesh DMs use the Noise Protocol (XX pattern), Nostr DMs use NIP-17 gift-wrapping.
• Multi-platform — native SwiftUI on iOS/macOS, Compose Multiplatform on Android/Desktop, all over one Rust core.

Architecture

Sonar is one headless Rust core, many thin app shells. The core owns identity, messaging, payments, and call signaling; each platform provides only the UI and the OS-specific bits (radios, storage, notifications, wallet).

core/                     shared Rust core (Cargo workspace)
├── sonar-core/           identity + Marmot (MLS over Nostr) + geohash + mesh + call signaling
├── sonar-ffi/            UniFFI bindings → Swift (xcframework) + Kotlin (.so / JNA)
└── sonar-ble/            desktop BLE bridge (CoreBluetooth/BlueZ over JNA; own workspace)

ios/                      native SwiftUI reference app (iOS + macOS)
apps/sonar/               Compose Multiplatform app (Android + Desktop JVM)
web/                      SvelteKit marketing landing page
relays/                   curated Nostr relay list
design/                   vendored design handoff (source of truth for the UI)
docs/                     protocol & feature specs (payments, discovery, calls, Tor, …)

The core is generated into each app by the build scripts in core/ (build-ios.sh, build-android.sh, build-desktop.sh) — they compile the Rust staticlib/cdylib and emit the UniFFI Swift/Kotlin bindings. The shipped binary artifacts (e.g. sonarffi.xcframework) are generated, not committed — rebuild them before archiving.

Transports

Bluetooth mesh (offline) — direct peer-to-peer within range, multi-hop relay (up to 7 hops), no internet required, Noise-encrypted with forward secrecy, over a compact binary protocol tuned for BLE.

Nostr (internet) — global reach over a distributed relay network, NIP-17 gift-wrapped DMs, ephemeral per-geohash keys for location channels.

Channel types

Channel	Transport	Scope
mesh #bluetooth	Bluetooth LE mesh	Local devices within multi-hop range — offline, protests, disasters, remote areas
Location (block #dr5rsj7, neighborhood #dr5rs, country #dr)	Nostr over internet	Geographic areas by geohash precision (block 7 → region 2 chars)

Account model

Your identity is a Nostr keypair (npub/nsec). The same key restores the same profile and the same Lightning wallet across devices and transports — a single person is one conversation whether they're reachable over BLE or White Noise.

For protocol detail, see the Technical Whitepaper, the Noise write-up in BRING_THE_NOISE.md, and the specs under docs/ — including Hermes Agent integration for headless sonar-cli + AI agents.

Platform support

Capability	iOS / macOS	Android	Desktop (JVM)
White Noise (Marmot) secure DMs	✅	✅	✅
Geohash channels + presence	✅	✅	✅
Encrypted media (MIP-04)	✅	✅	✅
BLE mesh — discovery	✅	✅	✅ (scan + advertise)
BLE mesh — messaging	✅	✅	⚪️ next stage (Noise-over-GATT)
Nearby payments over BLE (⚡PAY)	✅	✅	⚪️ later
Lightning wallet	✅ (Breez)	✅ (Breez)	⚪️ no desktop Breez build yet
Voice / video calls (☎CALL)	🚧 in progress	🚧 in progress	🚧

See apps/sonar/README.md for the full Android/Desktop matrix and its caveats.

Build & run

iOS / macOS

cd ios
open bitchat.xcodeproj

To run on a device:

• Copy the local config: cp Configs/Local.xcconfig.example Configs/Local.xcconfig

• Set your DEVELOPMENT_TEAM (and, if you fork it, PRODUCT_BUNDLE_IDENTIFIER / APP_GROUP_ID) in Configs/Local.xcconfig. The app group must stay group.<bundle id>.

• The Rust core is a generated artifact — rebuild it before building the app:

  ./core/build-ios.sh
  

For a quick macOS run from source: brew install just && just run (and just clean afterwards to restore the project for mobile builds).

Android / Desktop (Compose Multiplatform)

cd apps/sonar
./gradlew :composeApp:installDebug         # Android debug → device (arm64)
./gradlew :composeApp:assembleRelease      # phone APK (arm64 + armeabi-v7a)
./gradlew :composeApp:assembleRelease -Psonar.universalApk=true  # + emulators
./gradlew :composeApp:run                  # Compose Desktop

The Gradle build invokes the Rust core build (core/build-android.sh / build-desktop.sh) to produce the JNI .so / host dylib and the Kotlin bindings. Android details (secrets, ABIs, sideload): docs/ANDROID-BUILD.md.

Web (landing page)

cd web
npm install
npm run dev

Localization

• Base app resources live under ios/bitchat/Localization/Base.lproj/. Add new copy to Localizable.strings and plural rules to Localizable.stringsdict.
• Share extension strings are separate in ios/bitchatShareExtension/Localization/Base.lproj/Localizable.strings.
• Prefer keys that describe intent (app_info.features.offline.title) and reuse existing ones where possible.
• Compile-check localization changes: xcodebuild -project ios/bitchat.xcodeproj -scheme "bitchat (macOS)" -configuration Debug CODE_SIGNING_ALLOWED=NO build.