A Rate limit defines the number of unique calls (requests) that can be made to an API per window (a specific time period). For example, an API can have 1000 request per hour (window) but this is the total number of requests. This can be done to prevent an overloading of a system's infrastructure such as might be caused by a DoS (Denial of Service) attack or a DDoS (distributed denial-of-service) attack. Additionally, if requests to an API starts to become more active, the rate limit can be adjusted in steps to achieve optimum performance for users.
Each endpoint in a project can have a custom rate limit set. When maximum number of total requests sent by whomever are reached, an error will be returned.
To set endpoint rate limits, follow these steps.
From the Home menu, select API Publishing.
Select the menu for an endpoint (down arrow) to expand the endpoint form.
For no limit, leave the calls field blank and click Update.
For a custom limit, enter the number of calls and select a time period then click Update.