Your most used card, one press from the icon
On Android, long-pressing an app's icon shows a menu of shortcuts. In Kardpal those shortcuts open the cards you choose.
Up to three cards
In Settings, under App icon shortcuts, choose which card each shortcut opens. The shortcut takes the card's name, for example Supermarket.
The app must be installed
Shortcuts only exist when Kardpal is on the home screen. Android updates the menu by itself, usually within a day of the change.
On iPhone
Safari doesn't let web apps have icon shortcuts. On iPhone a favourite card at the top of the list is the quickest route.
One choice per phone
Shortcuts are set per device: your phone can open the supermarket card and your tablet the bookshop one.
Opens in your browser: no download, no sign-up. You can then add it to your Home screen.