Are Patterns The Same For Identical Data? - Feb 2017
If you were to encode the same data with the exact same settings using exactly the same QR Code generator then yes, it's likely that you will get the same output. But putting the same data into different generators can create different results even if your try to copy settings exactly.
When a QR code is generated it can use one of many modes to store character data. Some generators may allow the end user to specify which mode to use but others may analyse the data and make the decision for you. it's these different modes that are likely to give you different visual outputs.
Four of the modes are Numeric, Alphanumeric, Binary and Kanji/Kana. There is more info available on the data types and there limits Here.
More obviously, changing the level of compression or altering any other setting while keeping the same data to store, will see a change in the visual appearance of a code when compared.
If you're new to QR Codes and want to learn a little more, then take the time to read What's A QR Code
Or scan through our FAQs
If you want something a little more technical, try The Technical Stuff