Is there any guide about what it takes for Stripe to launch in a country? From this article it seems that it was entirely Stripe's choice to launch in Japan (rising culture of startups apparently) so why not entering the Eastern Europe (Poland. Croatia, Romania etc) too?

Take Romania for example, we would love to have a decent alternative to PayPal, are there any legislation impediments that prevents Stripe from entering here? Also, what exactly are the costs for Stripe when launching in a new country?