Add subscriber limit on metric (e.g. TOTAL_OPTIN_COUNT) where total limit amount will be bound to criterium1 (e.g. API_KEY) and limit is set for specified time period (e.g. HOUR).
Metrics: TOTAL_TRANSACTION_COUNT, TOTAL_OPTIN_COUNT, EXPENDITURE.
Criterium1: API_KEY,CONTENT_TYPE, SHORT_CODE, SUBSCRIBER_TYPE,ROUTE.
Period Unit: MINUTE, HOUR, DAY, WEEK, MONTH, YEAR

Language
Click Try It! to start a request and see the response here!