Which HTTP status code indicates that a client application is experiencing intentional rate limiting

202 Accepted means the request was received and will be processed asynchronously - it has nothing to do with rate limiting.

401 Unauthorized indicates missing or invalid authentication credentials, not rate limiting.

RFC 6585 defines HTTP status code 429 Too Many Requests specifically to indicate that the client has sent too many requests in a given time period and is being intentionally rate-limited by the server. The response may include a Retry-After header advising when the client can retry.

503 Service Unavailable indicates the server is temporarily unable to handle requests due to overload or maintenance, not intentional client-side rate limiting.