KBO.party offers the monthly KBO csv export as a REST service.
Free in beta
Lookup company by VAT id
kbo.party/api/v1/enterprise/719542535
kbo.party/api/v1/enterprise/998001128
kbo.party/api/v1/enterprise/956914601
Lookup establishment by VAT id
kbo.party/api/v1/establishment/2209809953
kbo.party/api/v1/establishment/2039214172
kbo.party/api/v1/establishment/2092219526