Countries · Netherlands

Netherlands: how to write an address

Address verification puts every address into the postal form of the country and checks it against the national address register: street, house number, postcode, coordinates. Here you'll find how to write an address there, what we check and three before-and-after examples.

Verify an address API documentation

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How address verification and duplicate detection work.

What an address looks like

House number·after the street (“Hauptstraße 5”)
Postcode·1234 AB; the country prefix in front (D-, F-, CH-) is removed
City·in capitals, in its local name
Country·country line and ISO code, in the reader's language

The Dutch postcode, four digits and two letters (“1012 PH”), identifies the stretch of street: with postcode and house number the address is already unique, and that is how forms and couriers use it. The house number follows the street, with any addition kept separate (“92-II”, “1 A”). The abbreviations “str.” and “ln.” expand to “straat” and “laan”, attached to the name.

What we verify

Addresses: the whole country · postcodes: 96% · data as of 12 Sep 2026.

Street·exists in the municipality, written in full and in the register's spelling; abbreviations are expanded in the country's language
House number·exists on that street; if the street exists and the number does not, the outcome flags it
Postcode·confirmed or filled in by the register, in the country's format
Coordinates·latitude and longitude of the house number, with the precision declared
Autocomplete·the street completes as you type, from the register; the house number and the postcode come with the selection (API)
WooCommerce · PrestaShop·autocomplete at checkout and order verification with the plugins

Bron: Kadaster — BAG · CC0

Before and after

Three addresses written the way people write them — abbreviated, without postcode, in lower case — and how they come out: public buildings and streets of the city centre, verified down to the house number.

damrak 1, 1012LG amsterdam → Damrak 1
1012 LG AMSTERDAM coordinates of the house number
kalverstr 92, 1012 PH amsterdam → Kalverstraat 92
1012 PH AMSTERDAM street written in full · coordinates of the house number
grote markt 2, 2011 XX haarlem → Grote Markt 2
2011 RD HAARLEM postcode fixed · coordinates of the house number

With the API

The same endpoint as every country: country_code is enough. The response carries the address in postal form, the outcome with the changes, and where the register is in service the coordinates, the municipality code and the district. Everything in the API documentation.

curl -X POST https://www.radaraddress.com/api/v1/contact \
  -H 'Authorization: Bearer YOUR_TOKEN' \
  -H 'Content-Type: application/json' \
  -d '{"address":"damrak 1","postcode":"1012LG","city":"amsterdam","country_code":"NL"}'

Frequently asked questions

Do you also verify addresses that are in a file?

Yes. In batch jobs a column with the country is enough, or the country set for the whole file: every row comes back in the country's postal form, with the outcome beside it and, where the register is in service, verified down to the house number.

What happens if an address is not in the register?

The outcome flags it. If the street exists and the house number does not, it points to the house number; if the street is not found in the municipality, the address still comes out in the country's postal form, with the warning.

Where do the data come from?

From the national address register, published as open data by the country's mapping or statistics agency, which we use under the licence it requires: Bron: Kadaster — BAG (CC0). The register is checked every night and reloaded when the source changes.

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