Each NFC chip has a UID - Unique ID - locked into the memory during production. With NTAG series chips this is a 7 byte 14 character ID similar to 04A1B2C3D4E5F6.
The UID is unique and it can be used to easily identify individual tags in use cases such as asset management. The UID can only be accessed using an NFC app. It doesn't present itself in the main memory space but you can duplicate it into the main memory by for example adding it dynamically to the end of a URL.
In some cases where the UID is being used as a identifier for the tag it's useful to know the list of UIDs supplied within a batch of tags. That's why Seritag offer a 'UID scan
' where we will scan the tags provided and supply a spreadsheet. For the large majority of cases - where a tag might be being used as a weblink for example - this is not required.
On genuine chips the UID cannot be changed. However it is possible - although not easy - to purchase and use some 'fake' chips where the UID can beSeritag - 01 May 2023