I've been googling to find out if there's a way to determine if one of my promo codes has been redeemed.
I've found solutions say use the redeem link in the iTunes mac app, enter the promo code (it will say if it's been redeemed) then when it asks for the password, click cancel.
However this no longer works, clicking redeem asking you for you user name and password as soon as you click the link.
Any ideas?
As far as I know, the only way to check if a promo code has been redeemed is Tokens.
It is a Mac application (FREE for one app, $29 for more) which allows you to generate, share and track them.
This is possible because instead of sharing the promo code itself, you will share a tokn.co URL containing your code. When a user redeem it, you can see "Redeemed" below the name of the person you shared the code with.
Unfortunately, I don't know if it also works with code generated using iTunes Connect but you can find more information on its website!