BeamIt

Share Files Between Any Devices — No App, No Signup, No Limits

One 6.9MB Go binary. Browser-based. WebRTC P2P with E2E encryption. Works across any networks, anywhere.

About

BeamIt is an open-source, instant file sharing tool that lets anyone share files between ANY devices, ANYWHERE — same room or different countries — using only a web browser. One 6.9MB Go binary. Zero configuration. Just run it. Same-network devices auto-discover; cross-network pairs use a short shareable code, a link, or a QR code. Transfers prefer WebRTC P2P, fall back through a built-in TURN relay, then a WebSocket relay — every path stays end-to-end encrypted and is verified with a streaming SHA-256.

beamit-cli-real.mp4

A real capture of the BeamIt CLI — start the server, hit its HTTP surface, watch two devices pair over the LAN, enable the built-in TURN relay, and shut down cleanly.

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Table of Contents

• About
• Features
• Installation
• Quick Start
• How It Works
• Usage Examples
• Why BeamIt
• Self-Hosting
• Contributing
• License
• Support

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Features

New in v1.1.0

• QR codes and auto-join links: Every sharing code renders a QR and a https://host/#BEAM-XXXX link. Scan the QR with a phone camera or open the link and the room joins itself — no manual code entry.
• Unlimited-size transfers: The receiver streams incoming chunks straight to disk with the File System Access API instead of buffering the whole file in memory, so multi-gigabyte transfers no longer exhaust the browser tab. Browsers without the API fall back to the classic in-memory download.
• End-to-end integrity: The sender hashes each file with a streaming SHA-256 and sends the digest in the final frame; the receiver hashes as chunks arrive and flags any mismatch. AES-256-GCM already authenticates every chunk; this catches truncation or reordering across the relay path too.
• Installable PWA: A service worker precaches the app shell so BeamIt opens instantly and works offline, with an in-app Install button.
• Built-in TURN server: --turn-secret starts a real TURN relay (pion/turn) with time-limited HMAC credentials, served to the browser via /api/turn, so strict-NAT peers stay end-to-end encrypted instead of dropping to the slower WebSocket relay.
• Per-transfer UX: Live speed and ETA, a cancel button, connection-mode badges (P2P / TURN / Relay), a screen wake lock so mobile transfers don't stall, and per-peer receive sessions so several peers can send at once.

Core Capabilities

• Browser-Based: Works on every device with a modern browser — no app to install, no signup
• True P2P via WebRTC: Direct device-to-device transfer when possible, fastest and most private
• E2E Encrypted: AES-256-GCM with per-peer ECDH key exchange on every path, including the TURN and WebSocket relays
• Cross-Network: Same room, same network, different countries — works anywhere
• Auto-Discovery on LAN: Devices on the same network appear automatically
• Single Binary / Self-Hostable: 6.9MB Go binary, two dependencies (gorilla/websocket, pion/turn), no database
• No File Size Limits: Streams straight to disk on the receiver — only your bandwidth matters
• Dark/Light Theme: System-aware, mobile responsive
• Text/Clipboard Sharing: Send snippets and links alongside files
• Room Codes, Links & QR: Cross-network pairing via short codes (e.g. BEAM-X7K2), auto-join links, or a scannable QR

Intelligent Connection Engine

Three-step strategy: P2P → TURN → relay. Always works. Always encrypted.

Step 1: WebRTC P2P direct (via STUN)
        ├── Success → fastest, most private
        └── Fail (strict NAT) →
Step 2: WebRTC via TURN relay
        ├── Success → still E2E encrypted
        └── Fail (TURN blocked) →
Step 3: WebSocket relay fallback
        └── Always works. Encrypted. Slower.

Sharing Modes

Same network and cross-network — both flows are first-class

Same Network (auto-discovery):

1. Person A opens BeamIt in their browser
2. Person B opens BeamIt on another device (same network)
3. Both devices appear automatically
4. Drag file → drop on device → instant P2P transfer

Different Networks (share a code, link, or QR):

1. Person A clicks "Get a sharing code" → gets BEAM-X7K2, a link, and a QR
2. A shares any of the three — the code, the https://host/#BEAM-X7K2 link, or the QR
3. Person B enters the code, opens the link, or scans the QR → the link/QR auto-joins, no typing
4. WebRTC P2P transfer, E2E encrypted, SHA-256 verified

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Installation

Pre-built Binary

# Download from releases page
curl -L https://github.com/cc1a2b/beamit/releases/latest/download/beamit-linux-amd64 -o beamit
chmod +x beamit
./beamit

Build from Source

git clone https://github.com/cc1a2b/beamit.git
cd beamit
make build
./beamit

Docker

docker run -p 8080:8080 -p 3478:3478/udp ghcr.io/cc1a2b/beamit

System Requirements

• Linux, macOS, or Windows (64-bit)
• Modern browser (Chrome, Firefox, Safari, Edge — anything with WebRTC)
• 6.9MB free disk for the binary

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Quick Start

./beamit

Open http://localhost:8080 in your browser. Done.

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How It Works

Same Network — automatic discovery

Devices on the same LAN find each other via mDNS broadcast. Drag, drop, transfer.

Different Networks — share a code, link, or QR

A short BEAM-XXXX code pairs two browsers across the internet. The same code is also rendered as a https://host/#BEAM-XXXX link and a QR — opening the link or scanning the QR auto-joins the room. WebRTC handles NAT traversal; the built-in TURN relay handles strict NATs; the WebSocket relay handles the rest.

Connection strategy

P2P first (fastest). TURN second (still encrypted, slightly slower). WebSocket relay last (always works).

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Usage Examples

# Default — HTTP on :8080
./beamit

# Custom port
./beamit --port 9090

# Start the built-in TURN relay (advertise your public IP)
./beamit --turn-secret "a-long-random-secret" --turn-ip 203.0.113.10 --turn-port 3478

# Enable HTTPS with cert + key
./beamit --tls-cert cert.pem --tls-key key.pem

# Development mode (CORS + verbose logging)
./beamit --dev --log-level debug

# Bind to a specific interface
./beamit --host 192.168.1.10 --port 8080

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Why BeamIt

Tool	Browser-based	Cross-network	True P2P	Simple UX	Single binary	Self-host	No limits
BeamIt	Yes	Yes	Yes	Yes	Yes	Yes	Yes
LocalSend	(app)	(LAN only)
PairDrop			(relay)		(Node.js)
ShareDrop		(LAN only)
FilePizza
wormhole.app			(cloud)				(10GB)
Magic Wormhole	(CLI)

BeamIt is the only tool that does all 7.

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Self-Hosting

# Run on your own VPS
./beamit --host 0.0.0.0 --port 80 \
         --tls-cert /etc/letsencrypt/live/share.example.com/fullchain.pem \
         --tls-key /etc/letsencrypt/live/share.example.com/privkey.pem

# With the built-in TURN relay for strict-NAT users
./beamit --host 0.0.0.0 --port 8080 \
         --turn-secret "a-long-random-secret" --turn-ip 203.0.113.10

Open UDP 3478 (or your --turn-port) so the built-in TURN relay is reachable.

Behind a reverse proxy:

location / {
  proxy_pass http://127.0.0.1:8080;
  proxy_http_version 1.1;
  proxy_set_header Upgrade $http_upgrade;
  proxy_set_header Connection "upgrade";
}

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Contributing

Contributions welcome from the open-source community.

• Report bugs via GitHub Issues
• Suggest features that respect the no-signup, no-app philosophy
• Improve documentation
• Submit pull requests for new transports, UI improvements, or self-host docs

Development Setup

git clone https://github.com/cc1a2b/beamit.git
cd beamit
go mod tidy
make build

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License

BeamIt is released under the MIT License. See LICENSE for details.

Copyright (c) 2024-2026 Hussain Alsharman
Licensed under MIT License — free for commercial and personal use

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Support

If BeamIt makes file sharing easier:

Star this repo • Follow @cc1a2b • Share with everyone

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BeamIt — Share Files Between Any Devices

Built by cc1a2b for the open web