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/468432202
kbo.party/api/v1/enterprise/597233849
kbo.party/api/v1/enterprise/582266551
Lookup establishment by VAT id
kbo.party/api/v1/establishment/2236779319
kbo.party/api/v1/establishment/2018191304
kbo.party/api/v1/establishment/2168988492