QR File Sender™

No signal? No Wi-Fi? You can still hand someone a file.

QR File Sender turns whatever you're sending into a stream of QR codes on your screen. The other phone points its camera at it and puts the file back together on the far side. That's the whole trick. Nothing to pair, nothing to log into, nothing uploaded anywhere, and neither phone needs a network at all.

One screen, one camera, and you're done.

Where it comes in handy
• On a plane, down in a basement, out on a trail, anywhere the bars have gone
• On a work phone where IT has switched off Bluetooth and nearby sharing
• When you'd rather not run a private document through somebody's cloud just to move it two feet
• Passing over a key file, a config, a signed PDF, a photo, a few notes

It puts up with a shaky hand
Most QR transfer apps fall over the moment the camera misses a frame, and you start again from the top. This one doesn't. Each frame is a piece of the whole file rather than "part 7 of 40", so the receiving phone keeps watching until it has enough to rebuild everything. Miss a few and you lose a second or two, not the transfer.

About the speed, honestly
It's a camera watching a screen, so it's nowhere near a cable. Depending on how dense you set the codes, the frame rate, and how still you can hold, you'll see somewhere between 4 KB/s and 55 KB/s. That's fine for documents, keys, contacts, config files, notes and small photos. It's not the way to move a two-hour film, and better you hear that now than after standing there with your arms up.

What's in it
• Any file type: photos, PDFs, zips, documents, keys
• Pick a handful at once and they go as one archive, so you only aim the camera once
• The receiving phone shows live speed, ETA, progress and how many blocks are in
• A SHA-256 check at the end, so you know it came through exactly as it left
• Optional AES-256 passphrase. Anyone filming your screen gets gibberish
• Sliders for code density and frame rate when you want to push it
• Brightness goes up while sending, because a brighter code reads faster
• A history of what you've sent and received, with save and share on anything that lands
• Works with everything switched off. The camera is the only permission it asks for

Getting a fast transfer
Hold both phones still and fill the brackets on screen with the sending phone. Sharp beats big: a smaller code in focus reads much faster than a large blurry one. Decent light helps. If it stalls, drop the density a step, because a code the camera can read beats a denser one it can't.

About your files
They don't go anywhere. No upload, no account, no sync, and nothing left on a server for you to delete later, because it never went to one. The app does check a small file for update notices when it opens, and that's the only thing it ever fetches.

Android 6.0 and up. Both phones need the app: one shows the code, the other reads it.