[ntpeters]

This is one reason I love Final: https://getfinal.com

Set up a separate card number for each site, and that way I don't have to worry if one site is compromised.

Disclaimer: Not affiliated at all, just a very happy customer! :D

[exikyut]

Is there an international version of this? (I'm in Australia.)

I maintain multiple cards with my bank to get a poor facsimile of this.

[TheMiller]

Discover had a service like this more than a decade ago, which I used quite a bit. But they shut it down after a few years.