All other hotel chains let you easily manage free night certificates online or in app; however, Hilton is always different about this issue. Previously, you not only can not book with a free night certificate online, but you also can not see how many of the certificates you have left and what their expiration dates are! You have to call Hilton to get this info. And their purpose is obvious: if you forget about the free night certificates and let them expire, then Hilton can save some money.
Now Hilton finally changed: you can see the free night certificates info online! Log into Hilton.com, and click your name in the upper right corner, and then click “Account”, then the info is shown at the bottom of this webpage:
It seems you still can not see this info on its mobile app, you can only see it in their webpage. It seems you can’t see this info if you don’t currently have an AmEx co-branded card, even if you had one and obtained a free night certificate which is still valid.
As of now, you still have to make a phone call if you need to book a night with the free night certificate.