Sendoso’s Marketplace / SmartSend APIs enforces rate limiting to ensure that the resources of the platform are shared fairly among all users and to prevent abuse or misuse of the API. Rate limiting is based on the number of requests made by an application or user within a given time period. Once the rate limit is exceeded, the API will return a 429 Too Many Requests response and the application will be temporarily blocked from making further requests. Currently, the rate limits for the Sendoso Marketplace and SmartSend APIs are as 100 requests per minute per user. If you exceed this limit, you will receive a 429 Too Many Requests response. The APIs return a X-Rate-Limit-Reset header in the response, which indicates the time at which the rate limit will reset. You can use this information to determine when you can make requests again.