SyncLan

SyncLan is a LAN-based instant messaging and file transfer application. It combines chatting and file sharing into a single interface. Once devices are discovered on the same Wi-Fi or local network, you can exchange text messages, images, and files as naturally as chatting. The desktop application runs the local service, while browsers can directly access and use it without installation.

Perfect for quickly sharing files and messages across multiple devices in offices, dormitories, home networks, air-gapped environments, or anywhere you don't want to rely on cloud storage.

English | 简体中文

Highlights

• 💬 Lark-inspired IM experience – The conversation list and chat interface are heavily inspired by Lark (Feishu), providing a familiar, polished, and intuitive messaging experience while dramatically lowering the learning curve for LAN file sharing.
• 🖼️ Pixel-perfect rich text editor – Supports rich text formatting, inline image previews, and incremental message history loading. The editing experience is carefully refined to match the smoothness of modern IM applications like Lark.
• 📁 LAN file transfer – Uploaded files are stored in a configurable local resource directory and shared with other devices through LAN URLs.
• 🖥️ Desktop + Browser – Built with Tauri for cross-platform desktop support while simultaneously serving a built-in web application accessible from any browser.
• 🔎 Device discovery – Automatically discover devices on the same network and start conversations instantly.
• 🔐 Optional HTTPS – Export a self-signed certificate and enable HTTPS after trusting it in your operating system.
• ⚙️ Highly configurable – Supports language, theme, launch at login, start minimized, automatic update checks, server port, upload directory, automatic cleanup, and more.
• 🧩 Built-in API documentation – Includes Swagger UI for API debugging and integration.

Screenshots

UI Design

The current SyncLan UI is mainly built with shadcn/ui, following its component style and design principles.

The project is still continuously improving its UI details. If you have better UI design suggestions, interaction improvements, or complete design proposals (Figma / Sketch / images, etc.), feel free to submit feedback or contribute design ideas. Together, we can make SyncLan's user experience even better.

Architecture

SyncLan adopts a "desktop-hosted services with browser-based clients" architecture, which differs from applications like LocalSend that require installation on every device.

1. A desktop instance is required. The SyncLan desktop application acts as the LAN hub. When launched, it starts both the IM service (Socket.IO) and the built-in web server.
2. Browser access for other devices. As long as one computer is running SyncLan Desktop, any other device on the same LAN can join instantly by opening the host's IP address in a browser—no installation required.
3. About mobile devices (iOS / Android). SyncLan relies on long-running background services that continuously provide IM and web server functionality. This architecture is not well suited to mobile operating systems due to battery usage and background execution restrictions. Therefore, native mobile applications are not planned, and mobile devices should simply access the desktop service through a browser.

Connection Flow

1. Launch SyncLan Desktop on the host computer.
2. Ensure all devices are connected to the same LAN or Wi-Fi, and the firewall allows SyncLan's configured port.
3. Desktop clients: Open Device Discovery, select a device, and start chatting.
4. Browser-only devices or mobile devices: Open the desktop server's LAN address directly in your browser.

The default local service runs on port 53317.

• Web UI: http://127.0.0.1:53317
• API Documentation: http://127.0.0.1:53317/api/docs
• Socket.IO: ws://127.0.0.1:53317/socket

Both the server port and upload directory can be customized in Settings.

Installation

Download Releases

If you simply want to use SyncLan, download the latest installer from GitHub Releases.

Build from Source

Requirements

• Node.js (latest LTS recommended)
• pnpm
• Rust (the repository includes rust-toolchain.toml)
• Tauri 2 system dependencies

The installation process differs slightly across operating systems. Please refer to the official Tauri documentation to install the required WebView runtime and toolchain.

Install Dependencies

pnpm install

Development

pnpm dev

Starts the Tauri desktop application in development mode.

Build Desktop Application

pnpm build

The generated packages are located under:

src-tauri/target/release/bundle/

Build Web Assets Only

pnpm web:build

Build Desktop UI Only

pnpm ui:build

Common Settings

Setting	Description
Language	Switch between Simplified Chinese and English.
Appearance	System, Light, or Dark theme.
Launch at Login	Start SyncLan automatically after login.
Start Minimized	Launch minimized to the system tray/background.
HTTP Server Port	HTTP service port. Default: 53317.
Enable HTTPS	Enable HTTPS after trusting the exported certificate.
Export Certificate	Export the self-signed SyncLan certificate.
Upload Directory	Directory used to store uploaded files.
Auto File Cleanup	Automatically delete uploaded files after a configurable period.
Auto Check Update	Automatically check for application updates.

Browser Access

When the desktop application is running, it serves the web interface automatically.

Devices on the same LAN can access it using the desktop machine's IP address, for example:

http://192.168.1.10:53317

If you cannot connect:

• Ensure both devices are on the same LAN or Wi-Fi.
• Make sure the desktop application is running.
• Check whether the configured port is blocked by the firewall, antivirus software, or router isolation.
• If HTTPS is enabled, ensure the SyncLan certificate has been trusted.

API

SyncLan uses Axum for its HTTP API and Socket.IO for real-time communication.

Once the desktop application is running, open:

http://127.0.0.1:53317/api/docs

to view the OpenAPI / Swagger documentation.

Main API groups:

• Synclan – Application authentication and common APIs.
• Device – Device information and discovery.
• Upload – File uploads.
• Message – Messaging and chat history.

Project Structure

.
├── src/                  # React frontend
│   ├── components/       # Shared UI, chat components, device discovery
│   ├── pages/            # Welcome, Chat, Settings, Profile, etc.
│   ├── lib/              # API, utilities, attachments, types
│   └── locales/          # Localization resources
├── src-tauri/            # Tauri / Rust backend
│   ├── src/server/       # HTTP API, Socket.IO, workers
│   ├── src/config/       # Configuration and encrypted fields
│   ├── src/core/         # Tray, logging, windows, startup
│   └── resources/        # Bundled web assets and database migrations
├── scripts/              # Release and helper scripts
├── package.json
└── Cargo.toml

Development Scripts

Command	Description
pnpm dev	Start the Tauri development environment.
pnpm build	Build desktop installers.
pnpm app:dev	Build the web application and preview the desktop UI.
pnpm app:build	Build both the web application and desktop UI.
pnpm web:dev	Start the browser development server.
pnpm web:build	Build browser assets.
pnpm ui:dev	Start the desktop UI development server.
pnpm ui:build	Type-check and build the desktop UI.
pnpm typecheck	Run TypeScript type checking.
pnpm oxlint	Run frontend linting.
pnpm format:check	Check frontend formatting.
pnpm test	Run Vitest tests.
cargo test -p synclan	Run Rust tests.
cargo fmt --all -- --check	Check Rust formatting.
cargo clippy -p synclan --all-targets -- -D warnings	Run Rust Clippy.

Troubleshooting

Devices Cannot Be Discovered

• Ensure all devices are connected to the same LAN.
• Temporarily disable VPNs, proxies, or guest network isolation.
• Verify that the system firewall allows SyncLan to use the configured port.
• Restart the local service after changing the server port.

Cannot Open the Web Interface

• First verify that http://127.0.0.1:53317 works on the host machine.
• Use the host machine's LAN IP instead of 127.0.0.1 on other devices.
• Ensure the HTTP Server Port matches the configured value.

HTTPS Certificate Not Trusted

SyncLan uses a self-signed certificate.

Export the certificate from Settings, trust it in your operating system or browser, restart SyncLan, and try again.

License

This project is licensed under the MIT License.