ArsDrop

Peer-to-peer file transfer via WebRTC — React 19, .NET 9, SignalR, Docker

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Overview

QR Pairing	Connected	Dark Mode

About

ArsDrop is a peer-to-peer file transfer tool that works directly between browsers. Files go straight from one device to another through an encrypted WebRTC connection — nothing is stored or passes through any server. Scan a QR code to pair devices, then send files of any size instantly.

Built with

• React 19 with TypeScript and Vite
• .NET 9 with SignalR
• Ant Design for UI components
• xUnit for unit testing (28 tests)
• Docker for containerization

Features

• Peer-to-peer file transfer via WebRTC DataChannel
• QR code pairing with automatic session refresh
• Real-time text sharing between devices
• Chunked file streaming with ACK-based reliability
• Transfer progress tracking per file
• Pause and resume file transfers
• Drag-and-drop file upload
• Screen Wake Lock to keep devices active during transfer
• Dark/Light mode
• i18n: Portuguese, English, Spanish
• Automatic reconnection with session persistence
• 256-bit cryptographic session tokens
• Rate limiting (10 creates/min, 30 validates/min per IP)
• Atomic session invalidation (only first receiver succeeds)

Architecture

┌──────────────┐                                  ┌──────────────────┐
│              │       SignalR (Signaling)        │                  │
│   Device A   │  <────────────────────────────>  │   ArsDrop API    │
│              │                                  │   .NET 9         │
└──────┬───────┘                                  └──────────────────┘
       │                                                  ▲
       │              WebRTC DataChannel (P2P)            │
       │        <─────────────────────────────────>       │
       │              Files never touch server            │
       │                                                  │
┌──────┴───────┐        SignalR (Signaling)       ┌───────┴──────────┐
│              │  <────────────────────────────>  │                  │
│   Device B   │                                  │   ArsDrop API    │
│              │                                  │                  │
└──────────────┘                                  └──────────────────┘

Backend:

ArsDrop.Api/
├── Controllers/   -> REST endpoints (create/validate session)
├── Enums/         -> Device role enum
├── Hubs/          -> SignalR hub (WebRTC signaling + authorization)
├── Models/        -> DTOs
├── Services/      -> Token generation and validation
├── Store/         -> In-memory session store with TTL
└── Extensions/    -> CORS, rate limiting

ArsDrop.Tests/     -> 28 unit tests (xUnit, NSubstitute, FluentAssertions)

Frontend:

src/
├── components/
│   ├── stages/    -> QrStage, ConnectingStage, ConnectedStage, FailedStage
│   ├── panels/    -> ConnectionPanel, FileTransferPanel
│   ├── drawers/   -> TransferSection, ShareSection
│   ├── layout/    -> PageLayout
│   └── ui/        -> CustomHeader, CustomQrCode, FileUpload
├── contexts/      -> Connection, Theme, Locale
├── hooks/         -> useOriginConnection, useFileOrigin, useQrCode, etc.
├── pages/         -> Home
├── i18n/          -> Locales (pt, en, es)
└── services/      -> API client

Installing and Running

Prerequisites

• .NET 9 SDK
• Node.js 22+

Local

1. Clone this repository git clone https://github.com/AdrianoReusSavi/arsdrop.git
2. Enter the project folder: cd arsdrop

Backend:

cd backend
dotnet run --project ArsDrop.Api

Frontend:

cd frontend
cp .env.example .env
npm install
npm run dev

3. Open http://localhost:5173

Docker

docker-compose up --build

• Frontend: http://localhost:3000
• Backend: http://localhost:5041

Tests

cd backend
dotnet test

Contribute

1. Fork this repository
2. Create a branch with your feature: git checkout -b my-feature
3. Commit your changes: git commit -m 'feat: My new feature'
4. Push your branch: git push origin my-feature

License

This project is under the MIT license. Take a look at the LICENSE file for more details.