Why use the Postalcode check API
User experience
Postal code data is validated real-time, simplifying and accelerating the order process for a better user experience for customers, less return shipments and a higher conversion rate.
Correct data structure
To provide the most recent and complete address data.
Easy to use
No need to fill in addresses completely in your checkout form. Entering postal code and house number is sufficient to automatically complete an address with street and city.
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Documentation
View our exhaustive documentation.
Postman
All of our API's available as Postman collections.
Github
Find PostNL on Github.
Sandbox
Test your integration by copying the endpoint.
Guidelines
Learn more about the Postalcode check API guidelines.
Using the API
The Checkout Postalcode Check provides an optimal way to implement the address verification in the webshop checkout.
General format (send any of a list of pre-defined fields). You can opt to require users to fill in a complete address (with all pre-defined fields that make up an address) or choose to choose a subset of fields. Unique Dutch addresses can be found based on the postalcode+housenumber+housenumberaddition (dependent on the existence of an housenumberaddition in the housenumber range). It can be attractive to use this subset instead of requiring users to fill out a complete address format.
Scenarios
Scenario 1; When a correct Postalcode, Housenumber (and Addition) combination was entered, the output should be a single output.
Scenario 2; When the Postalcode, Housenumber (and Addition) combination is not found, the output is an empty response. Like this: []