Send data with light
One screen shows the file as a light pattern, a phone camera reads it. No network, no cable, no upload – and every file arrives bit for bit.
Send a file through the screen as a modulated light pattern. Nothing is uploaded.
Fast works on most phones. If nothing arrives, choose Safe.
Your file travels only from screen to camera. Nothing is uploaded.
How it works
How it works
- 1
Add what goes in
Any file up to 16 MB – documents, pictures, archives, anything. Optionally protected with a password.
- 2
Start it
Set the speed (Safe, Medium or Fast), then start. Everything runs in this browser — no upload, no queue, no account.
- 3
Take the result
The SHA-256 ✓ is ready the moment the run finishes. Save it straight to your device.
What this tool does
- Send data with light
- The file travels as a grey wave pattern in two layers: if the camera shakes or the picture blurs, the fine layer drops out and the coarse one carries on. A fountain code and error correction make missed frames harmless, and a SHA-256 check at the end confirms the file is identical. The receiver automatically uses the signal layers its camera can reliably resolve.
When you need this
- A file has to get from an office PC to your phone, but the PC may not use Wi-Fi, Bluetooth or USB.
- You want to hand someone a document without sharing a network, an account or a cable.
Supported formats
Good to know
Frequently asked questions
Do both devices need internet?
Only to open this page once. The transfer itself runs purely from screen to camera; nothing is sent over a network.
How fast is it?
Roughly 15 to 30 KB per second on current phones, depending on the camera, the distance and how steadily you hold it. The frame in the viewfinder shows the distance that works best.
Is the file really identical?
Yes. Every piece carries a checksum and error correction, and at the end the whole file is checked with SHA-256. If anything were off, it would not be offered for saving.
What does the password do?
With a password the file is encrypted in your browser before it is turned into the light pattern (AES-256-GCM, key derived with PBKDF2 over 600,000 rounds). Whoever films the screen sees only encrypted data; the receiver needs the same password to restore the file. The password never leaves the device.
What files can I use here?
Any file up to 16 MB – documents, pictures, archives, anything. Optionally protected with a password.
What do I get back?
You get the original file back, byte for byte. Its SHA-256 hash is checked before it is offered for saving.
Does the file lose quality?
Nothing is lost. The file is not converted or re-encoded; what arrives is identical to what was sent.
When does it not work?
Needs a second device with a camera; glare on the screen and very shaky hands slow it down. Files up to 16 MB; large files take a few minutes.
Private by design
Your files stay on your device
The file only travels from screen to camera. Nothing is uploaded.