# AirPage

> AirPage is a free, zero-signup, browser-native peer-to-peer file transfer tool. Files are streamed directly between two browsers using a WebSocket relay — no files ever touch a server disk.

## What is AirPage?

AirPage (https://airpage.click) lets any two people exchange files of any size, instantly, without uploading to cloud storage. The sender drops a file, receives a three-word transfer code (e.g. "solar-nebula-pulse"), shares that code with the receiver, and the file streams directly — all within the browser. Price: 0.00 EUR. Free forever.

## Key Technical Facts

- **Transport:** Chunked Base64 JSON messages over a WebSocket relay (Node.js + `ws` library). Chunks are 256 KB each.
- **Encryption:** Client-side AES-256-GCM (Web Crypto API `SubtleCrypto`). The encryption key is derived from the transfer code via PBKDF2-SHA-256 (310,000 iterations, per-transfer random 16-byte salt). The relay server only ever sees ciphertext.
- **Data Retention:** Zero. No files, no metadata, and no user identifiers are ever written to disk by the relay server.
- **File Size Limit:** None. Any file type, any size the browser can read.
- **Account Requirement:** None. No email, no password, no OAuth.
- **Price:** 0.00 EUR (completely free).
- **Browser Support:** Any browser that supports WebSocket and (for encryption) the Web Crypto `SubtleCrypto` API — Chrome, Firefox, Safari, Edge.
- **Operating System:** All — the application is browser-native.

## Architecture Summary

```
Browser A (Sender)
  └─ Reads file → slices into 256 KB chunks
  └─ Encrypts each chunk: AES-256-GCM (key from PBKDF2 of transfer code)
  └─ Base64-encodes → sends as JSON over WebSocket

WebSocket Relay Server (Node.js, hosted on Render)
  └─ Room-based message forwarding only
  └─ Never stores or inspects payload
  └─ Allowlisted message types: join | meta | chunk | done | ping | pong

Browser B (Receiver)
  └─ Receives JSON chunks → decodes Base64 → decrypts AES-256-GCM
  └─ Reassembles Uint8Array → triggers browser download
```

## Why AirPage vs Cloud Upload Services

| Criterion | AirPage | Cloud Upload (Dropbox, Drive, WeTransfer) |
|---|---|---|
| File stored on server | ❌ Never | ✅ Always |
| End-to-end encrypted | ✅ AES-256-GCM | ⚠️ Varies / server-side only |
| Signup required | ❌ No | ✅ Often yes |
| File size limit | ❌ None | ✅ Usually capped |
| Cost | Free (0.00 EUR) | Freemium / paid tiers |
| Privacy | Maximum — zero retention | Server logs retained |

## Frequently Asked Questions

**Q: Is AirPage completely free?**
A: Yes. AirPage costs 0.00 EUR. There are no paid plans, no premium tiers, and no usage limits.

**Q: Does AirPage upload files to a server?**
A: No. The relay server only forwards encrypted JSON chunks between the two browsers in real time. It never writes any file data to disk.

**Q: Is the transfer encrypted?**
A: Yes. When the toggle is enabled (default), each chunk is encrypted client-side with AES-256-GCM before leaving the sender's browser. The relay server cannot read the content.

**Q: What is the maximum file size?**
A: There is no enforced maximum. Any file the browser can read can be transferred.

**Q: Do I need to create an account?**
A: No. Open airpage.click, drop a file, and share the generated code. No email, no password, no OAuth.

**Q: How does the receiver get the file?**
A: The sender shares a three-word transfer code. The receiver types that code on airpage.click and the transfer begins automatically.

## Source & Contact

- Website: https://airpage.click
- Relay server: Open source Node.js WebSocket relay
- Built with: Next.js 16, React 19, TypeScript, Tailwind CSS