Just like accessing almost any other API, the first step is the registration. We do that so we can plan infrastructure and resources better - and also to stop those few trying to abuse our API, and make life worse for all of us.
Thankfully, registration is simple (and free): Head to https://dev-portal.at.govt.nz/, click on the “sign up” button, and fill in the details. Afterwards, you’ll receive a confirmation email; click on the link - and you are good to go.
To use an API, you will need to subscribe to it: Go to “products”, and select the product “Developers” (at the moment there is only this one), and give it the name of your application. That product grants you access to 600 calls/minute, and 35,000 calls/week - should be plenty to start? Afterwards, you’ll receive a primary and secondary key.
You can use either of these keys for your application - they are there if you want to switch to a new key for an upgrade (rolling upgrades), or to grant temporary access. See the Microsoft Azure Team Blog for details.
Once you have an app production-ready, you may need more calls than the “developers” product allows. Please get in contact with us then (preferably a bit earlier), so we can check that we have enough resources for your app.