NIS codes are five-digit codes that uniquely identify geographic areas in Belgium. If you enable enrichment for Belgium, a verifier returns a nine-digit code that contains the five-digit NIS code and a four-digit Neighborhood ID.

For example, a verifier returns

21004A001

as an enrichment to the following address:

Rue au Beurre 1
1000 Bruxelles
BEL

In this example,

21004

is the NIS code and

A001

is the Neighborhood ID.