Why it matters
A 304 Not Modified response tells Google to reuse its copy, so unchanged pages cost almost nothing to recrawl. Google lists HTTP cache control among the ways to manage crawl budget, and its crawling team has said it prefers ETag.
How to meet it
Send a strong ETag (a hash of the content) or Last-Modified on HTML and on the JS, CSS and API responses used for rendering, and answer If-None-Match or If-Modified-Since with 304 and no body when nothing changed. Derive the ETag from the content only, not from timestamps, nonces or session data, and keep it identical across CDN nodes.
How to test it
curl -sI https://www.example.com/page shows an ETag; repeating the request with -H 'If-None-Match: "<etag>"' returns 304. The Crawl stats response breakdown shows 304 responses.
How Regensbot covers it
Decided from one URL.
An audit reads the response, the headers, the HTML, robots.txt, the sitemaps and the structured data, and the finding shows the evidence it saw.
Sources
Google documents02
- 01Optimize your crawl budgetGoogle (opens in a new tab)
- 02Crawling December: HTTP cachingSearch Central blog (9 December 2024) (opens in a new tab)
Claims in the knowledge base05
- D1-C104SourceHow Google thinks about crawl budgetGoogle's documentation
- D1-C103ConsistentHow Google thinks about crawl budgetShown on screen
- D1-C321ConsistentHow crawling worksSaid on stage
- D1-C350ConfirmedHow crawling errors affect SearchSaid on stage
- D1-C384ConsistentHow Google thinks about crawl budgetSaid on stage
Claim IDs refer to the Search Central Live 2026 knowledge base. The knowledge base (opens in a new tab)
- Confirmed
- Google's documentation states the same thing.
- Consistent
- Google's documentation supports it without stating it.
- Source
- The claim is the cited document itself.