- Class
- C4 Informational
- Weight
- 0
- Severity on fail
- info
- Applies to
- Any engine
Scope and evidence
Evaluated on preferred origin. The book marks this requirement OPTIONAL.
Observations
Each condition has a stable code and a reason template. The evaluator fills the placeholders from observed values only; no sentence in a report is generated.
supports_304The home page answered 304 to a conditional re-request. Google's crawlers treat 304 as a signal that the content is the same as last time it was crawled.
no_304The home page sent {validator} but answered {status} to a conditional re-request instead of 304.
Sources, quoted
These are the passages the rule rests on, stored once in the knowledge base and emitted exactly as written. A citation marked for specific conditions appears only on findings with those codes.
“signal the next processing system that the content is the same as last time it was crawled.”
[G-HTTP] How HTTP status codes, and network and DNS errors affect Google Search · 3xx (redirection) · last updated 2026-02-04
https://developers.google.com/crawling/docs/troubleshooting/http-status-codes