HTTP 499 Client Closed Request is a non-standard status code used by nginx to indicate the client closed the connection before the server finished responding. This commonly occurs when: users navigate away before a page loads, API clients time out waiting for a response, load balancers close idle connections, or mobile users lose network connectivity. While not part of any RFC, 499 appears frequently in nginx access logs and monitoring dashboards.
Response includes the status code, standard headers (including Content-Type), and a small diagnostic JSON body describing the request and returned status.
Simulator URL (copy in the app after load — not a normal link):
https://httpstatus.com/api/status/499
Example request:
curl -i "https://httpstatus.com/api/status/499"