I had this exact thought. Unfortunately I can't find a way to check the balance of an Apple gift card without signing in to an Apple ID⁽¹⁾. So maybe you need a throwaway Apple ID...
⁽¹⁾ https://support.apple.com/en-us/108111
I guess a throwaway account would be essential then. That's a little weird to require an ID just to check the balance.
I guess a throwaway account would be essential then. That's a little weird to require an ID just to check the balance.