A Rate Limit for an API specifies the highest number of requests that a client is permitted to send to an Application Programming Interface (API) during a defined time period. This control is vital for preserving the reliability, efficiency, and protection of APIs by stopping excessive use that might cause service impairment or interruptions.
API rate limiting is a technique implemented to regulate the volume of incoming and outgoing traffic to or from a network. By establishing a cap on the number of API calls a user or application can perform within a particular timeframe, rate limiting guarantees that the API stays accessible and quick to respond for all valid users.
Without rate limiting, APIs risk being flooded with too many requests, which can reduce performance or result in service failures.
One widely used approach to API rate limiting is throttling. It temporarily constrains the frequency of incoming requests by either reducing response speeds or completely rejecting them once the threshold is reached. Throttling can be implemented at various levels, such as across the entire API, per individual user, or application.
API rate limiting fulfills several essential purposes: