How do I make my app check a serial ?

hi i would like to achieve this

when someone use my app, the app check a serial on a server (txt file).

then the app check if the serial in the server match the serial inside the app, if it match then the app start if not, it closes !

how can i achieve that ?

thanks

a txt file? I'm not sure whether it's possible or not, but Im pretty sure you could use an array and use a .JSON file and then do what is says here(https://www.construct.net/en/forum/construct-2/general-discussion-17/text-search-80830)