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Speed & Delivery

Cache Header Checker

Inspect Cache-Control, ETag, Expires and Last-Modified.

Free, no signup. We fetch the page once and read what your server sends back.

Fetching the page…

What this checks

Caching headers decide whether a returning visitor downloads your page again or reads it from their own disk. Get them right and repeat visits are close to instant.

  • Cache-Control
  • ETag
  • Expires
  • Last-Modified

How to act on the result

  • HTML usually wants a short max-age. Static assets want a long one plus a versioned filename.
  • No Cache-Control at all means browsers guess, usually conservatively.
  • ETags let a browser revalidate cheaply instead of re-downloading.

Frequently asked

What is a good Cache-Control value?

For HTML, a short max-age such as 600 seconds. For versioned CSS, JS and images, max-age=31536000 with immutable, because the filename changes when the content does.

Does caching affect SEO?

Indirectly through speed, and directly through crawl efficiency: a well-cached site is cheaper for Google to crawl.

What is an ETag?

A fingerprint of the response. The browser sends it back and the server can reply "not modified" without resending the body.

Why is my page not caching?

Commonly a Cache-Control: no-store from a session or cookie layer, often set sitewide when it was only needed on logged-in pages.

Want all 40 checks at once?

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