Rate-limiting is a mechanism used to control the number of requests that can be made to a server within a certain time period. It helps prevent abuse, protect server resources, and ensure fair usage. By implementing rate-limiting, developers can set limits on the number of requests that can be made by a client or user, preventing them from overwhelming the server with excessive requests. This can be particularly useful in scenarios where there is a need to protect sensitive data, prevent unauthorized access, or maintain the overall performance and stability of the server.