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/539651580
kbo.party/api/v1/enterprise/707857401
kbo.party/api/v1/enterprise/923016267
Lookup establishment by VAT id
kbo.party/api/v1/establishment/2160549690
kbo.party/api/v1/establishment/2090273685
kbo.party/api/v1/establishment/2232509636