There is a maximum limit of 1000 requests per minute. The account of the limits is always expressed in the return of each API:
{"object": "list","data": [],"has_more": true,"count_api": 4,"reset_count_api": 45}
"count_api" field is the count of API calls made
"reset_count_api" field is the remaining seconds when the count_api is reset
When api call limit reached, an error message will be returned with code: 400 and message: "FLOOD_WAIT_x" where X represents the seconds to wait before call a new API.