first of all, 57k in NL is definitly NOT top segment. thats mid level. top segment for seniors is more like 80k to 95k.

thats a huge difference already!

also mind that those online figures not necessarily include 8% vacation money, 13th month, 25-30 days pto and pension fund (up to 100%, usually 50%)

source: i had this salary myself after 6 yrs and subsequently hired a lot of people in this segment for roughly that amount.

contractors can demand even more. its not unlikely for React senior people to charge 100-120 p.h.