Free HTTP Caching & Compression Checker
Enter a page address and see how it is cached and compressed, with advice on what to change to make repeat visits faster.
Free, with no sign-up. Fair-use limits apply. To enforce them we keep the domain you enter and a scrambled form of your IP address for 30 days, as described in our privacy policy.
Why caching matters
Good caching lets a browser or CDN reuse a file instead of downloading it again. Compression shrinks what is sent. Together they are among the cheapest ways to make a site faster, which helps visitors and Core Web Vitals.
How to use it
Enter a page address and press Check caching. We fetch it with and without compression and read the Cache-Control, Expires, ETag and Last-Modified headers. You get a list of findings and the values found.
What to aim for
HTML should usually be revalidated often, while fingerprinted scripts, styles and images can be cached for a year. Every text response should be compressed. For a wider check of your response headers, use the security headers checker.
Frequently asked questions
What is the difference between gzip and brotli?
Brotli usually compresses smaller. Either is far better than nothing.
Should HTML be cached?
Briefly, or revalidated with an ETag. Long caching of HTML delays updates.
Does it check images and scripts?
It checks the page you enter. Use the image audit for images.
More free tools
See all free tools, or read about the Domain Tools in the dashboard.