When you sign up for Duffel, you'll pick a currency. We'll use it for almost everything. If you've not topped up yet, email us to change it.
When you sign up for Duffel, you'll pick a currency that you want to pay in. This will be used as the currency of your Balance, the flights you book (assuming that you're using Duffel's airline relationships) and your Duffel fees.
If you want to change your currency after signing up, drop us an email at firstname.lastname@example.org. We'd strongly recommend doing this before you make your first top-up.