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/577009745
kbo.party/api/v1/enterprise/880285391
kbo.party/api/v1/enterprise/873263086
Lookup establishment by VAT id
kbo.party/api/v1/establishment/2173360224
kbo.party/api/v1/establishment/2202175162
kbo.party/api/v1/establishment/2228004480