Transfer small files using only a screen and a camera.
No pairing. No shared Wi‑Fi. No cloud upload. Works offline after your first visit. One device shows a stream of QR codes; the other watches through its camera until the file is rebuilt — and verified — locally.
files processed in your browser no account, no install designed for small files & text
01 — How a transfer works
Three steps, no setup
Open Send on one device
Pick a file or paste text. Your browser splits it into hundreds of coded frames and starts playing them as a rapid QR sequence.
Open Receive on the other
Point its camera at the first screen. Frames can be missed, repeated or caught out of order — the fountain code doesn't mind.
Verify and save
Once enough frames arrive, the file is reassembled and checked against its SHA‑256 hash. Only a byte-perfect copy is offered for download.
02 — What it's for
Honest limits, by design
LightDrop is a light-based clipboard between devices, not a replacement for AirDrop or a USB drive. It shines exactly where those fail — when two devices can't, or shouldn't, share a network.
- Best for text, links, JSON, configs, tickets and small images — we suggest staying under 10 MB.
- Slower than any network transfer. A 1 MB file typically takes under a minute at close range.
- Needs a screen on one side and a camera on the other, in the same room.
- The QR stream is visible light: anyone who can film the screen can read it. Don't send passwords or private keys.
- Works in the browser over HTTPS — nothing to install, nothing uploaded to a server.
03 — Common questions
FAQ
Does my file ever leave my device over the internet?
No. The file is read, encoded, displayed, captured, decoded and verified entirely in the two browsers involved. The transfer itself uses no network path — only light between the screen and the camera. Our server only delivers the app's static pages.
Do both devices need to be online?
After your first visit, LightDrop installs as an offline-capable web app. From then on, both the Send and Receive pages work with no connection at all — airplane mode included.
What happens if the camera misses some frames?
Nothing bad. The stream uses a fountain code: every frame is a fresh random combination of the file's pieces, so any sufficient set of frames — in any order — rebuilds the file. There is no "please resend frame 42".
Is this secure?
The transfer has no network path, and integrity is verified with SHA‑256 — but the codes are visible on screen, so anyone filming the screen could capture them. Treat it like reading something aloud in a room. Details on the security page.
How fast is it?
With default settings (30 frames per second, ~1.4 KB per frame) throughput is tens of kilobytes per second. Small files finish in seconds; a 10 MB file is a coffee-break affair. It's the wrong tool for videos.
Which browsers work?
Recent Chrome and Edge on desktop, Safari on iPhone and Chrome on Android. Receiving requires camera access, which browsers only allow on HTTPS pages.