Thanks for the question, @johnny.a.fernandes. We are long overdue for an update to our docs, but I promise we’re making progress!
The info provided by @peter and @btst.online is correct. The development API key has been around since the first version of our API and was included to give users a simple way to get started, but it was never intended to be used in a production environment. It has volume restrictions and will be deprecated soon. The next update to the API documentation will be consistent with the data access policy, and will focus on the access token concept, which will be the normal way developers will interface with the API (with an API key only required for “enterprise” users).
And don’t worry: we will give folks plenty of time to update code before the dev key stops working!