German banks have had HBCI later FinTS for decades[0]. What I don't know is why that standard ended up in new Fintech banks rolling their own standards later on

German banks have had HBCI later FinTS for decades[0]. What I don't know is why that standard ended up in new Fintech banks rolling their own standards later on. I suspect the implementation, certification and licensing must be a nightmare, but I really don't know. [0] https://en.wikipedia.org/wiki/FinTS https://en.wikipedia.org/wiki/FinTS