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/799000282
kbo.party/api/v1/enterprise/609386167
kbo.party/api/v1/enterprise/451519063
Lookup establishment by VAT id
kbo.party/api/v1/establishment/2009648275
kbo.party/api/v1/establishment/2062759240
kbo.party/api/v1/establishment/2022072985