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Transfers files between two phones with no Wi‑Fi, no Bluetooth and no network by…

2026-07-31 · 05:00 UTC ·@om_patel5 ·1 min read

Brief

A developer built a phone-to-phone file transfer that requires only a screen and camera: one phone flashes animated QR codes continuously, the other captures them and reconstructs files using fountain codes. The linkless system achieves ~129 kb/s (2 MB images in seconds), tolerates dropped frames and mid‑stream joins, and is an open-source prototype (≈375 stars) created in one night with Claude code.

Why it matters

Transfers files between two phones with no Wi‑Fi, no Bluetooth and no network by one device flashing an endless stream of animated QR codes on its screen while the other records with its camera—no pairing, no app, no shared network required.

Key details

  • Throughput around 129 kb/s (a 2 MB image transfers in seconds); there is no back channel so the system uses fountain codes (each frame is a scrambled mix of the file), letting the receiver collect frames in any order and reconstruct once it has enough — mid‑stream joins and dropped frames only slow, never break, the transfer.
  • Creator built a working prototype in one night using Claude code; the implementation is open source and the repo has about 375 stars.
Source evidence

SOMEONE BUILT A WAY TO SEND FILES BETWEEN TWO PHONES WITH NO WIFI, NO BLUETOOTH AND NO NETWORK AT ALL

it works with just a screen flashing qr codes at a camera

one device plays an endless stream of animated qr codes, the other one points its camera at the screen and rebuilds the file out of the light

no pairing, no app, no shared network, nothing but the camera

> its pulling about 129 kb/s, a full 2mb image transfers in seconds
> theres no back channel, the receiver can never ask for a missed frame, so it uses fountain codes, every frame is a scrambled mix of the file rather than one piece of it
> that means the receiver just collects any frames it can catch in any order, and once it has enough it can reconstruct the whole file
> dropping frames costs you a little time but never breaks the transfer
> you can point the camera at a stream thats already running and it just locks on mid flight

he was building a cached mp3 player because he was sick of ads and bad streaming quality. he wanted a way to send tracks phone to phone without both phones being on the same network, and realized flashing qr codes could carry the data

he built the whole working prototype in one night with claude code

its open source and already at 375 stars

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