Which HTTP response status code indicates that too many requests have been sent to the API?

The HTTP 429 response status code is specifically used to indicate that the user has sent too many requests in a given amount of time, commonly referred to as "rate limiting." This response serves as a precautionary measure, helping protect the API from being overwhelmed by excessive traffic. When an API server responds with a 429 status, it typically includes headers that indicate how long the client should wait before sending more requests. This allows the system to maintain performance and availability, ensuring that services remain reliable for all users.

In contrast, the other status codes serve different purposes: a 404 response indicates that the requested resource could not be found, a 500 response signifies a server error indicating something went wrong on the server side, and a 200 response indicates that the request was successful and the server processed it properly. Each of these codes is critical for understanding different situations within an API context, but only the 429 code directly addresses the issue of rate limits and excessive requests.