I think my Zalando gift cards expire after 4 years.
It's pretty much a universal API credit policy at this point. I'm not sure if this legitimately escapes the prepaid gift card requirements or if the providers see nuance where there might not be any.
Where I live (in Canada) it's actually illegal for gift cards to ever expire, and there's lots available from US companies, so if it's an accounting issue other companies have figured it out.