https://mbarlow.github.io/thinair/
Device to device transfer, just a static github page.
gh repo: https://github.com/mbarlow/thinair
Creates QR codes for each device to scan for webrtc. Android to android will do an audible chirp that lets the devices know to switch from qr code mode to opening the camera to scan each others codes. Tested android to apple and working, the audio chirp doesn't get caught by apple. Just wait and eventually the qr code will dissolve to allow scanning step.
Just threw this together. I was playing with audio handshake using bird-like chirp "songs" or old school modem between smartphones. Fun putting phones together as they send audio frames and confirm to start transfer, but unreliable and slow to handshake. I would like to cleanup the flow to improve. I've started using it for sending files between iphone/android/pc without having to deal with apps, emails, accounts, etc. blah.
Whenever I need to use something like this it's because the device isn't mine, which makes this so much better than an app. Would be cool if there was a text message option, and a bit of server so the second scan wouldn't be required. Pretty funny how simple the concept is though.