Wrong QR-Code generated via QtQr

i am facing problem generating Qr code i find my self with two different result using different tools

  1. the first photo is for qr code generated by online tool (correct one )
Raw text	


Raw bytes	

71 a4 1e c2 a8 21 2d 35   c3 be c2 b2 49 c2 a8 c3
84 62 c2 be c2 ae c3 a6   41 3b 3d c3 9a 71 c3 a6
48 00 

Barcode format	QR_CODE
Parsed Result Type	TEXT
Parsed Result	

  1. the second photo is for qr code generated by QtQr:
Raw text	


Raw bytes	

42 1e fb bb fc 2a 82 12   d3 5c 3b ec 2b 24 9c 2a
8c 38 46 2c 2b ec 2a ec   3a 64 13 b3 dc 39 a7 1c
3a 64 80 ec 

Barcode format	QR_CODE
Parsed Result Type	TEXT
Parsed Result	


Hard to tell from screenshots (bad: You should have used copy+paste and proper formatting) but “Parsed Result” looks the same?

but the raw byte not the same

Tools do it differently.

Does both QR codes work (ie, do as expected)?

only the online one work correctly

Okay. I’ve used qrencode before and that seems to work.

but this tool only for generating qrcode

Yes. I thought you wanted to generate working QR codes?

Final version of package qtqr was released 2011-07-10 - QR Tools 1.2 Released

Last announcement dated 2021-02-23 advised the project was End of Life


I’m officialy announcing that I have stopped working actively on the project and I don’t think I’ll be working on it in the future. I’m still open to merge pull request and patches sent by the community though at least until the project finds a new home or we manage to enable other people on Launchpad.

If you read the documentation for creating qr-codes you will see that there are several ways to create a valid code for the same text.
So there is no “binary compatibility” to verify. “raw bytes” may differ, but in the end they code for the same “url” or text.

This is like compiling a program.

The same sourcecode will result in different binaries if you use different compilers (or different options). BUT all those binaries do the same.

You can see that both codes are correct, because the parsed result is the same !



Here is the link to the original repo for QR-code generators, where you can find different versions for different languages:

There is quite a few ways to generate qr-codes.

If it is a simple link - the pattern is the binary representation of the text you supplied - but it may be more complicated as you can embed images in the qr - and there is various degrees of error correction you can use when generating the qr - so there is no guarantee they are binary identical.

You have to realize that the more complex the content the qr-code becomes more and more detailed depending on complexity.

This created using QtQR with different datatypes and as is apparent - although the text is the same - they are not binary identical

QtQR Text datatype


QtQR Url datatype


Generated using the online tool you referenced choosing a text which resembles a hostname will generate an url qr - that must be some logic the hostmaster implemented.

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