You can call API via GET or POST requests. Set your API key as x-api-key as http header (secure method) or just include as request parameter in get or post request.
Technology is nothing. What is important is that you have a faith in people, that they are basically good and smart, and if you give them tools, they will do wonderful things with them.
Steve Jobs (Former co-founder, chairman, and chief executive officer (CEO) of Apple Inc)