Peer-to-peer text chat for devices on the same local network, powered by Rust and libp2p. Run a desktop peer, connect from a browser or Android phone, and exchange messages on a shared channel. Native peers can discover each other automatically with mDNS; explicit addresses work when discovery is unavailable.
- Desktop CLI ↔ Android over TCP, with Noise transport encryption and signed messages.
- Browser ↔ native peer over WebSockets, including browser-to-browser messages through that peer.
- React and Solid 2.0 RC clients with editable peer addresses, connection status, error reporting, and disconnect/reconnect controls.
- Android foreground chat with configurable dialing, retained UI state, and private per-installation identity.
- Local send confirmation after publication is accepted. This is not confirmation that another device received the message.
Verified LAN baseline: Linux/macOS native checks, both browser production builds, Chromium messaging/reconnect tests, and Android arm64 APK assembly/lint pass. Two-way messaging was also verified between a Mac, an Android emulator, and a physical Samsung phone on the same LAN. The implementation is merged into main; verification details record the tested revisions and remaining limits.
Install Rust stable with edition 2024 support and Node.js 24+ with npm. Then clone and prepare the browser target:
git clone https://github.com/sam-a1a/P2P-Chat.git
cd P2P-Chat
rustup target add wasm32-unknown-unknownIn one terminal, start a desktop peer:
cargo run -p p2p-chat-cli --lockedIn a second terminal, from the repository root, choose a browser client:
| Client | Install and build | Start | URL |
|---|---|---|---|
| React | npm --prefix web/react ci && npm --prefix web/react run build |
npm --prefix web/react run dev |
http://127.0.0.1:5173 |
| Solid 2.0 RC | npm --prefix web/solid ci && npm --prefix web/solid run build |
npm --prefix web/solid run dev |
http://127.0.0.1:5174 |
Open the chosen URL, keep /ip4/127.0.0.1/tcp/9090/ws, and select Connect. Wait for connected, then send a message. Type a reply in the desktop terminal. Type quit there to stop the desktop peer.
The build generates the shared WASM bindings before type checking and bundling. Run the client's build:wasm script after changing the Rust browser transport. The first build downloads WASM tooling; npm setups that block install scripts must allow the wasm-pack installer.
Keep the desktop peer running and substitute its LAN IP in the address:
| Connecting client | Peer address |
|---|---|
| Browser on the desktop machine | /ip4/127.0.0.1/tcp/9090/ws |
| Browser on another LAN machine | /ip4/DESKTOP_LAN_IP/tcp/9090/ws |
| Physical Android phone or another desktop peer | /ip4/DESKTOP_LAN_IP/tcp/53493 |
| Android emulator on the desktop machine | /ip4/10.0.2.2/tcp/53493 |
For a browser on another computer, run its web client locally using the quick-start commands and change the Peer address field. Browser peers dial a native peer; they do not use native mDNS or accept TCP connections.
Allow TCP 53493 and 9090 through the desktop firewall. Both listeners bind to all interfaces by default. An HTTPS-hosted UI requires a secure wss endpoint; the supplied local setup uses plain WebSockets with Noise-encrypted peer traffic. See architecture.
| Path | Purpose | State |
|---|---|---|
core/ |
Rust networking, identities, JNI/C FFI | Implemented |
desktop/cli/ |
Desktop command-line peer | Implemented |
web/wasm/ |
Browser libp2p peer | Implemented |
web/shared/ |
Browser lifecycle, events, styling | Shared by both UIs |
web/react/ |
React chat client | Implemented |
web/solid/ |
Solid 2.0 RC chat client | Implemented; prerelease framework |
mobile/native-android/ |
Kotlin/Compose + JNI | Implemented |
web/svelte/ |
Svelte client | Planned |
mobile/native-ios/, mobile/flutter/ |
iOS and Flutter clients | Planned |
desktop/native-{macos,windows,linux}/ |
Native desktop GUIs | Planned |
The planned folders contain documentation only. They are not runnable applications.
cargo run -p p2p-chat-cli -- --help
cargo run -p p2p-chat-cli -- \
--identity /tmp/second-peer/identity.key \
--tcp /ip4/127.0.0.1/tcp/53494 \
--websocket /ip4/127.0.0.1/tcp/9091/ws \
--dial /ip4/127.0.0.1/tcp/53493Use a distinct identity path and ports for each local node. Type quit to stop. mDNS discovers LAN peers; explicit dialing works when multicast discovery is unavailable.
Requires JDK 21 or newer (set JAVA_HOME), Android SDK 37.0, Android NDK 29.0.13846066, and Rust Android targets.
cargo install cargo-ndk --version 4.1.2 --locked
export ANDROID_NDK_HOME=/path/to/android/sdk/ndk/29.0.13846066
bash core/build-android.sh
cd mobile/native-android
./gradlew assembleDebug lintDebug
adb install --no-streaming -r app/build/outputs/apk/debug/app-debug.apk
adb shell am start -n com.example.p2p/.MainActivityThe native build script accepts optional Rust targets, e.g. bash core/build-android.sh aarch64-linux-android. Full builds produce arm64, armv7, and x86_64 libraries. APK builds require those native libraries to provide messaging; Gradle does not generate them automatically.
Successful CI runs also provide an android-debug-arm64 APK artifact. It is a development build for arm64 devices, not a signed store release. With multiple devices attached, select one using adb -s DEVICE_SERIAL.
In the app, enter /ip4/DESKTOP_LAN_IP/tcp/53493 and tap Connect. The Android emulator can use /ip4/10.0.2.2/tcp/53493. Keep the app open during chat; background delivery is not implemented.
cargo fmt --all -- --check
cargo clippy --workspace --locked --all-targets -- -D warnings
cargo test --workspace --locked
cargo build -p p2p-chat-cli --locked
npm ci
npm --prefix web/react ci
npm --prefix web/solid ci
npm run build:web
npx playwright install chromium
npm run test:e2eNative tests exercise TCP/WebSocket exchanges, failures, and identity persistence. Browser tests launch an isolated real desktop peer and verify React/Solid messaging, invalid addresses, disconnect, reconnect, and cross-client exchange. See verification for the current evidence and remaining limits.
| Symptom | Check |
|---|---|
| Connection times out | The native peer is running, the address uses its reachable LAN IP, and the firewall allows the correct port. |
| Browser cannot connect | Use port 9090 with /ws; the native TCP port 53493 is for Android/desktop peers. |
| Android cannot connect with its default address | 10.0.2.2 is an emulator address. On a phone, enter the desktop's LAN IP or use automatic LAN discovery. |
| Send is disabled | Wait for the peer's chat subscription to be ready. A socket connection alone is insufficient. |
| Android reports a missing native library | Run core/build-android.sh for the device ABI before assembling the APK. |
| Port is already in use | Stop the other node or supply different CLI listener ports and a distinct identity path. |
Dependencies and toolchains were updated on 2026-10-16. Lockfiles pin reproducible builds, and Dependabot checks supported ecosystems weekly. Solid uses 2.0.0-rc.15; upstream libp2p constraints require compatible WASM binding versions rather than independently selecting the newest binding packages. See dependency versions and exceptions.
This is an online shared-channel LAN chat, not a production private messenger. Transport uses Noise encryption and messages have libp2p signatures. All peers subscribed to chat can read and forward messages. There is no room membership control, user authentication, offline delivery, message history UI, NAT traversal setup, or integrated end-to-end group encryption. core/src/crypto and storage are separate utilities, not part of the current message path. The field named ciphertext in native events currently carries plain message bytes after transport decryption.
Each native installation generates an identity.key. Keep it private; losing it changes your peer ID. Keys committed in old revisions are public and must not be reused. Stop the node, remove old root/core/Rust-Core keys obtained from the repository, and restart. New Unix keys are owner-only; Android excludes its key from backups. History has not been rewritten.
See contributing, architecture, and issues. Keep changes scoped to focused issues and commits. The completed LAN baseline was merged in PR #8; the planned platform clients above remain future work.