QR File Transfer: No cables, no accounts, just scan

Why another file sharing tool?

I got tired of sending files to myself via email, Telegram, or Google Drive just to copy a script or APK from my desktop to my phone. AirDrop only works on Apple devices. I needed a zero-configuration, cross-platform solution that worked over the local network.

How it Works

The system utilizes three core steps:

1. Start a local HTTP server on the computer.
2. Auto-detect the computer's local network IP address (e.g., 192.168.1.15).
3. Generate a QR code in the terminal containing the server's URL.

You scan the QR code with your phone, and it opens a simple, responsive web application where you can upload or download files instantly at local Wi-Fi speeds.

Auto-Detecting the Local IP in Node.js

Here is how the tool gets the active local interface IP address dynamically:

const os = require('os');

function getLocalIP() {
  const interfaces = os.networkInterfaces();
  for (const name of Object.keys(interfaces)) {
    for (const iface of interfaces[name]) {
      // Skip internal (loopback) and non-IPv4 addresses
      if (iface.family === 'IPv4' && !iface.internal) {
        return iface.address;
      }
    }
  }
  return 'localhost';
}

const localIP = getLocalIP();
console.log(`Server running at: http://${localIP}:8080`);

Adding WebSockets for Real-Time Progress

To show progress bars on both the sender and receiver screen, I integrated a basic WebSocket server. When a phone starts uploading a 100MB file, the Node.js server streams the chunks to disk and updates the desktop display in real time. It is secure, operates 100% offline, and is incredibly fast.