I am getting "Too Many Requests" response.
Depending on your account, there is limit on how many request you can send per minute. If you exceed this limit, you will get this response.
I am getting "Monthly limit of * request used up" response.
You account has a fixed monthly limit of request. If you exceed that limit, you will get this message. This limit is reset every month.
How can I increase my usage limit?
We are providing basic usage for free. If you want to increase your limit, please contact us.