Documentation - PostNL

API Integration

With these and the API key, you can start testing in the sandbox environment or production environment. The details on the API usage can be found on our developer portal (such as the Shipping API:https://developer.postnl.nl/browse-apis/send-and-track/shipping-webservice/)

Plugins and PUDO selector for webshops

Plug-ins | PostNL
https://developer.postnl.nl/plug-ins/

overzicht-plug-ins-webwinkels-04_tcm10-234270.pdf
https://www.postnl.nl/Images/overzicht-plug-ins-webwinkels-04_tcm10-234270.pdf

Products

List of product codes
https://developer.postnl.nl/browse-apis/send-and-track/products/

Self service implementation

This means your systems would manage the label creation, the barcode number allocation, and the EDI data will be pushed in bulk. It's suitable in cases in which label retrieval needs to be < 2 seconds or so, otherwise the API returns labels in 500ms, up to 3-4 seconds.
Specifications for Self-Implementation