Hello,
We are building web tool and i found your API very interesting which can be good for my project. We are making tool; where we i future will required your Vast amount of API Consumption so in future if ut suits with my application we will go for paid version. But before that i need to check your API how its going. Can you please brief me more about this.
but when i tried to work with your Gtmatrix tutorial it give me following error.

{“error”: “Invalid e-mail and/or API key”}