Requests are limited to 5 per second, 50/min, 200/hour, 2000/24hours, 3000/week. Max age for timestamp parameter: 30 days
Freekey helps to easily start developing your project. It's not recommended to use freekey in a product mode.
Requests per second: 10 Max count of transactions/operations in response: 1000 Max age for timestamp parameter: 1 year
Only one API-key should be used per project. Creating several keys, IP addresses, and exceeding the project limits violates our policy. Please do not do that. For multiple addresses tracking use Bulk API
See also: How to get a personal API key?