This article explains that Double the Donation does provide services to Australian organizations, but the companies offering matching gift programs in Australia tend to be more limited than in the US.
At Double the Donation our goal is to track all companies with matching gift programs regardless of their location. And we have a variety of companies either based in Australia or who are global companies with employees in Australia. That being said, matching gifts originated in the US and have since expanded internationally to countries like Canada, Western Europe, and Australia (the trend among companies is expanding their programs globally).
So yes, we do have clients in countries outside of the US, but the matching gift programs aren't offered by as many companies.