Romania. I'm registered as a "persoana fizica autorizata" (PFA), which has 2 types of taxation systems: - real (which means you're taxed ~40% based on how much you earn). - norma de venit, where you'll need to pay taxes for a fixed amount of money, even if you make less. This system is only for persons making below 100k eur/year, after that you'll be moved to the "real" taxation.

In op case, he exceeds the 100k limit and he'll need to register a company instead where there's a 3% revenue tax plus a 5% income tax.

In Poland software engineers are able to pay 5% linear income tax if they can proove they do R&D and sell copyrights to their code. The rules seem to be quite loose in this regard and thus lots of developers qualify for the discount.