Camera + screen
Visual Transfer
Encodes the file into a stream of QR frames. Best choice for speed and reliability when one device can see the other screen.
Browser-to-browser • no file server
Serverless File Transfer
Move files directly between nearby devices without uploading the file to this Flask server. Choose a visual QR transport or an audio transport.
Speaker + microphone
Audio Transfer
Measures the room, selects a quiet frequency band, synchronizes acoustically, and transfers the file using sound only.
What “serverless” means here
Flask serves the application files, but the transferred file itself does not pass through Flask. Visual mode moves data through displayed QR frames; audio mode moves it through speaker-to-microphone tones.