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/900978659
kbo.party/api/v1/enterprise/885692548
kbo.party/api/v1/enterprise/727024106
Lookup establishment by VAT id
kbo.party/api/v1/establishment/2190184477
kbo.party/api/v1/establishment/2167882494
kbo.party/api/v1/establishment/2006068777