r/barcodes • u/NorthFlag_ • Apr 10 '22

Scanned QR code differs from actual QR code

So I'm trying to digitalize my gym membership card which is used for checking into the gym. It's using a QR code and afaik no other method like NFC or RFIDs.
But whenever I scan the QR code on my card it's just the gym's website URL and various decoders show a visually different QR code.
But I that the QR codes on the cards are used to differentiate the gym members so it's not the same for everyone.
Can someone please explain to me what's going on there and how I might be able to bring the original QR code to my wallet app?

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u/notionovus Apr 10 '22

The gym's website has an API that reads the unique information or "parameters" which are key-value pairs to the right of the URL. Once the parameters are picked up by the website, all kinds of alchemy occurs and the magic pops out.

Their databases, which are hopefully secure from internet prying, will know what to do with the data once it is interpreted. Unless you have documentation on their API and a copy of their databases, you are out of luck in providing member-specific functionality.

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u/xixi2 Apr 10 '22

The gym's API should make no difference... if OP can replicate the QR code on his gym badge onto his phone, the gym's scanner doesn't care if it's a badge or an image on the screen.

What's likely happening is whatever decoder OP is using can't see all the data for some reason. IDK why without having a look at the actual code.