What does a NotFound response from a service indicate?

A NotFound response from a service, typically represented by an HTTP status code of 404, indicates that the requested resource could not be found. This response is considered an expected restriction rather than an error because it signifies that the request matches a valid endpoint, but the specific resource being requested does not exist.

In many cases, this can be a perfectly valid response if, for instance, the resource was deleted, moved, or never existed in the first place. Such responses are part of standard web service behavior and inform the client that while the service is functioning correctly, the desired data is not available. This is distinct from an error, which would imply a problem with processing the request itself.

Understanding that a NotFound response indicates a specific expected condition allows developers to handle these responses gracefully in client applications, leading to better user experiences, as the client can adjust expectations accordingly without overreacting to the absence of a resource.