SecureTransfer is a high-performance, real-time file-sharing system built on the WebRTC protocol. It enables fully peer-to-peer (P2P) transfers, ensuring your files never touch a central server.

SecureTransfer uses a Signaling-First, P2P-Second approach. While the server helps peers find each other, it never sees the file data.

sequenceDiagram
    participant S as Sender (Peer A)
    participant SS as Signaling Server (Node/Socket.io)
    participant R as Receiver (Peer B)
    
    S->>SS: Generate Offer
    SS->>R: Relay Offer (via Link/Email)
    R->>SS: Generate Answer
    SS->>S: Relay Answer
    Note over S,R: WebRTC Data Channel Open (P2P)
    S->>R: Stream File Chunks

Screencast.from.2025-12-18.21-48-23.mov

SecureTransfer relies on WebRTC Data Channels to facilitate direct communication between browsers.

1. The Handshake: The Sender creates a room, which generates a unique WebRTC "Offer."
2. Signaling: The Receiver joins via a shared link or email invitation. We use a Socket.io signaling server to exchange connection metadata.
3. The Connection: Once the peers find each other via STUN servers, the connection becomes purely P2P.
   • Note: Success rates for STUN-based connections are typically around 80%. If a connection fails, it is usually due to restrictive firewalls (Symmetric NAT), not the software itself.
4. The Transfer: Files are broken into small chunks, sent over the data channel, and reassembled in real-time on the receiver's end.

Handling files over 1GB without crashing the browser was the primary challenge.

• Memory Management: To avoid memory overflow, we don't load the whole file at once. We slice the file into ArrayBuffer chunks.
• Reassembly: On the receiver side, we manage Uint8Array fragments, ensuring they are reassembled in the correct order to maintain file integrity.

• Frontend: React (UI & WebRTC implementation)
• Signaling Server: Node.js (Express & Socket.io)
• Email Queue: BullMQ + Redis (Handles invitation delivery)
• **UI Design and implementation is done by Kushal Aryal

Access the UI

• Frontend: http://localhost/5173

// run command from the root
docker compose up -d

• Node.js installed
• Redis server running (for BullMQ)

cd backend
npm install
# Configure your .env file (see .env.example)
npm run dev

cd backend
npm run worker

cd frontend
npm install
npm run dev

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