Authorised offline transfer only

Browser-only optical file transfer.

Secure, offline file transfers using QR handshakes. No backend. No network. Just light between two screens.

No backend Local processing Camera + QR only

File contents are displayed as QR codes on screen. Anyone with line of sight can capture them. No network transfer occurs.

Pick a role

Open Sender on one device or window, Receiver on the other.

How it works

1
Grant camera access

Enable local browser permissions. The video feed never leaves your device — it stays in RAM.
2
Align QR + ACK

Position the receiver toward the sender's screen. A handshake establishes the channel.
3
Transfer at light speed

Watch the patterns sync. The file is reconstructed bit-by-bit locally on the receiver.

Diagnostics & system logs

ENGINE OK

No diagnostics run yet.
> _

Manual test runner

No manual test run started yet.

Sender

Sender Mode

Prepare a file locally, display one QR frame at a time, and wait for receiver acknowledgements.

IDLE

Outgoing QR Frame

Acknowledgement Camera

Watching for ACK

Select a camera to scan receiver acknowledgements.

Camera

Transfer Status

IDLE

Progress 0.0%

Transfer ID: -
Current chunk: -
Total chunks: -
Retries: 0
Timeouts: 0
Throughput: -
Next timeout: -
Avg ACK latency: -
Adaptive actions: 0
Last ACK: -

File & transfer settings

Source file(s) Payload mode Chunk size Error correction Encoding Frame dwell Advance mode Transfer mode ACK timeout Max retries Compress transfer bytes with DEFLATE Simple mode: show INIT first, then loop DATA frames without receiver ACKs Encrypt transfer with passphrase (AES-GCM) Sender passphrase Auto-tune chunk size downward after repeated timeouts

Select a file to estimate QR payload reliability.

File preview

Filename: -
MIME type: -
Original size: -
Transfer size: -
Estimated chunks: -
SHA-256: -

Session summary

Frames shown: 0
ACKs accepted: 0
Duplicates: 0
Elapsed: -

Receiver

Receiver Mode

Scan the sender QR stream, acknowledge valid frames, rebuild the file in memory, then download.

IDLE

Incoming Camera Feed

Point at sender QR

Point this camera at the sender QR.

Acknowledgement QR

Camera & scan control

Camera Receiver passphrase Simple mode: expect a sender INIT that disables ACK QR replies

Waiting to start the camera.

Progress

IDLE

Received 0 / -

Transfer ID: -
Received chunks: 0
Total chunks: -
Duplicates: 0
Invalid frames: 0
Scan stalls: 0
Missing chunks: -
Last event: -

Final file

Filename: -
Size: -
Expected hash: -
Reconstructed hash: -

Session summary

Frames accepted: 0
ACKs shown: 0
Duplicates: 0
Elapsed: -

Browser-only optical file transfer.

Pick a role

Send a file

Receive a file

How it works

Grant camera access

Align QR + ACK

Transfer at light speed

Diagnostics & system logs

Manual test runner

Sender Mode

Outgoing QR Frame

Acknowledgement Camera

Transfer Status

File & transfer settings

File preview

Session summary

Receiver Mode

Incoming Camera Feed

Acknowledgement QR

Camera & scan control

Progress

Final file

Session summary