I will answer for KredoBank - I myself would be glad to cut down such a thing (I myself need it).
KredoBank uses the iFOBS system for legal entities, and there is nothing like a REST API there.
At most, you can manually receive an XML file from the ifobs windows client, send it manually to onebox, it parses it and downloads payments. This seems to have even been done once, but it did not take root.
I think that with the Raiffeisen plus or minus the same story.
Although there is some strange document
http://1991.vc/otpbank-api.pdfIn general, it is better to first find out if there is an API for Kredobank.