To gain some experience with APIs, I chose to implement the Google Maps JS API for one of my recent projects. Check out my work, specifically the branch where the action happened, on GitHub or see the an example of the map on Heroku.
After implementing the map and tweaking the display properties just a bit, I was worried that I was able to see my referral key in the URL through the DOM inspector. I reviewed the documentation from Google and it seemed that I was doing everything correctly. To double check, I read through some other posts. To triple check, I got on the Odin Project gitter.im and, as always, I got some help that reassured me that everything was ok.