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/964945310
kbo.party/api/v1/enterprise/228413323
kbo.party/api/v1/enterprise/442773227
Lookup establishment by VAT id
kbo.party/api/v1/establishment/2108682703
kbo.party/api/v1/establishment/2041005011
kbo.party/api/v1/establishment/2141766235