XMLdation validation services listed in this page are made based on specifications released by NVB, the national financial organisation in Netherlands.
Payment types defined by NVB are based on pure ISO 20022 schemas (xsd). XMLdation validation service contains schema restrictions, as well as all business rule checks derived from the implementation guides published by NVB.
The detailed information about the schemas and implementation guides can be found by selecting an item from the list below.
The home page of the organisation is located at: http://www.betaalvereniging.nl/europees-betalen/
XMLdation's validation tool links to the following, service specific wiki regarding some of the validation rules: https://wiki.xmldation.com/Support/NVB
However, some business rules specified in the NVB implementation guide are derived from general level specifications, like ISO20022 or EPC, and in these cases the wiki pages made for these organisations are often used instead.