My iPhone's camera unable to scan bar codes

Test the macro mode on your iPhone:

Take macro photos and videos with your iPhone camera - Apple Support

If it works there to focus on close objects, then there is no fault in the camera itself and the problem almost certainly lies with the app developers.

Regards.

The app is using the wrong lens. Try backing up so camera to barcode is 12 inches to 18 inches. If that doesn’t work developer will need to update app.,

It’s because you’re too close. As I stated above, you need to start at about 12” and back up from there. Put the focus point on the barcode and long press to fix the focus point. Backup from 12” and long pressing on the barcode each time. The barcode doesn’t need to be that large in the frame, but it must be in focus.

This is a user-to-user forum, no Apple-employed developers read here. If your response was from a 3rd party app developer they are probably passing the buck because they can’t fix it.

Are you using the barcode scanner in the Control Center?

First, try moving the camera further away. After that, contact the app developer and complain that their app’s camera feature doesn’t work.

I’ve never seen one. The single-line barcode is straightforward; there’s really only one format.

QR codes are different. A QR code that opens a URL is one type (and I think the only one that iOS can deal with), but you can encode almost any text in a QR code.

At the risk of straying off-topic …

… is there a list of barcode formats which the iOS’ built-in scanner will successfully interpret?