HTTP status explainer
Look up an HTTP status code, its class and caching meaning.
- HTTP status codes
- Status class and cacheability
What it means
Status code404
Reason phraseNot Foundadvisory only; clients must not depend on the wording
Class4xx Client error
MeaningThe server has no representation for this URL
Defined inRFC 9110
Cacheable by defaultYesheuristically cacheable without explicit headers (RFC 9110 §15.1)
How clients behave
Indicates an errorYes
Whose faultThe request
Body expectedUsually
Safe to retry automaticallyNo
The 4xx class
Class meaningThe request was malformed or cannot be fulfilled as sent
Codes in this class29
Lowest in class400
Highest in class451