Citi has long offered virtual card numbers as an option from their website.
With a VCN you can set a dollar limit or expiration date to a one-time use number so that you don’t keep getting charged for subscriptions or have your real card number stolen, among myriad other potential uses.
Unfortunately they have removed the functionality from all of their American Airlines cards.
VCNs are still offered on other Citi cards, but Citi sure hasn’t invested in their future. It still runs on Adobe Flash, and Chrome browser support for Flash is in its final year.
You can still use VCNs with Capital One, but Bank of America killed off their VCNs last year. Will Citi do the same?