Simple definition
An HTTP status code is a three-digit result indicating whether a request succeeded, redirected, or encountered an error.
Purpose and use
An HTTP status code classifies a request's result so the client can decide how to continue.
How does it work?
The 1xx family is informational, 2xx signals success, 3xx covers redirection or conditional use, 4xx indicates request-side issues and 5xx server-side failure.
Example and verification
During an incident, record the exact code and the component producing it: application, reverse proxy, CDN or another intermediary.
Points to watch
A 404 does not always prove nonexistence, and a 200 can contain a business error. Interpretation also depends on content and logs.
In short
Status provides a standardized result category that must be related to actual service behavior.