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/724955036
kbo.party/api/v1/enterprise/947230437
kbo.party/api/v1/enterprise/764134623
Lookup establishment by VAT id
kbo.party/api/v1/establishment/2190494382
kbo.party/api/v1/establishment/2132794923
kbo.party/api/v1/establishment/2092491027