dx034 parent
Of course they do. Their APIs are just way worse and documentation can be really bad as you have to connect to decades-old systems. But once it's up and running they will honor their agreement.
I've had a front row seat to many occasions where they did not honor their agreement. Really, e-commerce is so much easier nowadays mainly because you no longer have to deal with banks for the basics. Other than creating your bank account (which, at the moment can take anywhere from three to six months depending on which bank you choose where I live).