After all those new-ish, app-based banks are for people with too much time on their hands. You mostly can't talk to anyone, and when they answer it's just a copy-paste from their FAQ. They also lack features, e.g. Kontist doesn't support international bank transfers. Support will tell you "well it could work, but we can't give you any assistance". I don't have six months until your development team understands and implements some protocol!