LINKDROP

Browser-to-Browser File & Text Sharing

---

Overview

LinkDrop is a peer-to-peer file and text sharing tool. Files travel directly between two browsers using WebRTC — the server never sees, stores, or touches your data. The signaling server exists only to introduce two peers to each other, then steps aside completely.

---

How It Works

Sender's Browser                              Receiver's Browser
       │                                               │
       │         Signaling Server (Socket.io)          │
       │◄──────── peer introduction only ────────────► │
       │                                               │
       └─────────── WebRTC P2P Direct Transfer ────────┘
                    server never sees the file

1. Sender selects files or text, sets a password, clicks Create Link
2. A unique password-protected link is generated
3. Receiver opens the link and enters the password
4. Content transfers directly between browsers — no upload, no cloud, no server

---

Features

• Any file type — .exe .zip .mp4 .iso .apk .pdf — zero restrictions
• Unlimited file size — only browser memory is the limit
• Up to 5 files at once with full folder selection support
• Text sharing — send code snippets, notes, or links alongside files
• Password protected — every transfer requires a password to access
• Reload-safe — received files persist in IndexedDB until downloaded
• Sender protection — browser warns before tab close until receiver saves
• Zero server storage — nothing is ever written to disk on the server
• Dead link detection — invalid or expired links show a 404 instantly
• Fully responsive — works on mobile, tablet, and desktop

---

Architecture

┌─────────────────────────────────────────────────────────────┐
│                      LINKDROP SYSTEM                        │
├──────────────────┬──────────────────┬───────────────────────┤
│   Sender         │ Signaling Server │   Receiver            │
│   Browser        │ (Socket.io)      │   Browser             │
│                  │                  │                       │
│  Files/Text  ──► │ room created     │                       │
│  Password set    │ peer introduced  │ ◄── Link opened       │
│  Link shared ──► │ handshake done   │     Password entered  │
│                  │                  │                       │
│  ◄───────────────────── WebRTC ─────────────────────────►   │
│         Direct P2P — server completely bypassed             │
└─────────────────────────────────────────────────────────────┘

---

Tech Stack

Layer	Technology
Frontend	React 18 + Vite
Fonts	IBM Plex Mono + Bebas Neue
P2P Transport	Native Browser WebRTC — RTCPeerConnection
Signaling	Node.js + Express + Socket.io
Client Storage	Browser IndexedDB
Security	SHA-256 password hashing in-browser

---

Project Structure

linkdrop/
├── client/
│   ├── src/
│   │   ├── lib/
│   │   │   ├── peer.js          # WebRTC P2P send & receive logic
│   │   │   ├── idb.js           # IndexedDB session persistence
│   │   │   └── icons.jsx        # SVG icon components
│   │   ├── pages/
│   │   │   ├── SharePage.jsx    # Sender interface
│   │   │   └── ReceivePage.jsx  # Receiver interface
│   │   ├── App.jsx
│   │   ├── main.jsx
│   │   └── index.css
│   ├── index.html
│   ├── vite.config.js
│   └── package.json
│
├── server/
│   ├── server.js                # Signaling server
│   └── package.json
│
├── .gitignore
├── LICENSE
└── README.md

---

Security

• Passwords are hashed with SHA-256 before leaving the browser — plaintext never transmitted
• The signaling server stores only the hash — never the password itself
• Files never touch the server — pure browser-to-browser transfer
• Each session link is a UUID v4 — cryptographically unguessable
• Links are live only while the sender's tab is open — no persistent exposure

---

Author

Sambhav Dwivedi

• Website: https://sambhavdwivedi.in

---

License

Copyright © 2026 Sambhav Dwivedi. All Rights Reserved.

See LICENSE — unauthorized use, copying, or distribution is strictly prohibited.

---

_{Built with WebRTC · Zero Server Storage · P2P Direct · Password Protected}