When you are on the free plan and your daily quota is used up, the API will respond with the error code 402 and no more calls can be made until your quota resets.
You have complete control over your quota by looking at your console dashboard and checking the API response headers that appear with every answer from the API. These response headers are:
X-API-Quota-Request
: The number of tokens used.X-API-Quota-Used
: The number of tokens used in total today. This number resets to zero at midnight UTC (click here to compare to your local time zone).X-API-Quota-Left
: The number of tokens left today (depends on your plan)There is a limit of how many requests you can make per second. The limits depend on the plan you are on. If you try making more requests you will receive a 429 error.