Linking X1 Credit Card Account

Hi! Has anyone successfully linked an X1 credit card? I was a Mint user for years and was able to link my X1 card in there despite X1 not having a traditional web banking username/password type login. I ditched Mint when it became Credit Karma and was hoping Tiller could be my replacement, but I need to be able to link my most used card.

What is the URL for the online account login? I can check on that for you.

We have a list of many of the banks we support here.