A lot of APIs will use an API key that is sent in the query string for authorization. The API key could be called anything, depending on the API you are using. It might be labelled ‘api_key’, ‘apikey’, ‘key’, ‘token’, ‘client_secret’ or whatever the API decides to call it. An example might look something like this, using ‘api_key’ as an example:
https://myapi.com/myendpoint?api_key=abcdef12345
This is very simple to achieve using WPGetAPI. You simply need to add your API keys details into the ‘Query Variables’ section within the WPGetAPI plugin, as shown below. This will then automatically create the correct query string for you.