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/212744655
kbo.party/api/v1/enterprise/643506809
kbo.party/api/v1/enterprise/782176227
Lookup establishment by VAT id
kbo.party/api/v1/establishment/2257245626
kbo.party/api/v1/establishment/2185948250
kbo.party/api/v1/establishment/2158004728