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/500004415
kbo.party/api/v1/enterprise/790003137
kbo.party/api/v1/enterprise/659927820
Lookup establishment by VAT id
kbo.party/api/v1/establishment/2174396639
kbo.party/api/v1/establishment/2155185194
kbo.party/api/v1/establishment/2252734136