You bring up some other really valid points: - Exchange rates; if you charge in EUR and settle in GBP, a charge of 0,66% will be added.
- Test and production is almost the same; before you go live, your account will be in test mode, and after you are live you will always be able to send in "test=true" to make test transactions. No separate environments (unless you create multiple merchant accounts, which you can).
- Price; We'll charge a percent fee for all European countries except for Sweden which also has a fixed transaction fee.
Bedsides that, we also support Invoice, PayPal, DirectBank and Swish. Let me know if you have further questions or feedback!
Best, Robert