Snapdrop — Local File Sharing PWA via WebRTC

Introduction

Snapdrop is a progressive web app that enables peer-to-peer file sharing between devices on the same local network. It uses WebRTC for direct device-to-device transfers with no file size limits, no uploads to external servers, and no account required. Open it in a browser on any device and start sending files.

What Snapdrop Does

• Automatically discovers other Snapdrop-enabled devices on the same local network
• Transfers files directly between browsers using WebRTC data channels
• Sends short text messages between devices via the same interface
• Works on any device with a modern browser including phones, tablets, and desktops
• Operates as a PWA installable on home screens for quick access

Architecture Overview

Snapdrop uses a lightweight Node.js signaling server that helps devices on the same network discover each other via WebSocket connections. Once two peers are connected, the signaling server brokers a WebRTC handshake. After that, all file data flows directly peer-to-peer through WebRTC data channels, never touching the server. The server only sees device metadata for discovery purposes.

Self-Hosting & Configuration

• Deploy with Docker using the linuxserver/snapdrop image or clone the repo and run with Node.js
• The server requires only Node.js and npm with no database or external dependencies
• Configure the listening port via environment variables; default is port 3000
• Place behind a reverse proxy like Nginx or Caddy for HTTPS, which is required for WebRTC on most browsers
• Network isolation ensures only devices on the same subnet see each other

Key Features

• Zero-config peer discovery using local network broadcast via WebSocket rooms
• End-to-end transfer with no server-side file storage or cloud dependency
• No file size limit since transfers happen directly between browsers
• Cross-platform support across Windows, macOS, Linux, iOS, and Android browsers
• Lightweight server footprint suitable for Raspberry Pi or any small host

Comparison with Similar Tools

• PairDrop — community fork of Snapdrop with additional features like room-based sharing and multi-file transfer improvements
• LocalSend — native desktop and mobile app using a custom protocol; requires installation rather than a browser
• AirDrop — Apple-only; Snapdrop works across all operating systems and browsers
• KDE Connect — Linux-centric with Android support; Snapdrop is fully browser-based and platform-agnostic
• Wormhole — cloud-relayed encrypted transfer; Snapdrop is local-only with no cloud involvement

FAQ

Q: Do files pass through the Snapdrop server? A: No. The server only handles device discovery. Files transfer directly between browsers via WebRTC.

Q: Does Snapdrop work across different networks? A: By default it only discovers devices on the same local network. For cross-network sharing, you would need a TURN relay server.

Q: Is there a file size limit? A: No hard limit. Transfer speed depends on your local network bandwidth and browser memory.

Q: Can I use Snapdrop without self-hosting? A: Yes. The public instance at snapdrop.net is available, though self-hosting gives you full control and privacy.

Sources

• https://github.com/SnapDrop/snapdrop
• https://snapdrop.net