Cache-Control Header Builder
Build an HTTP Cache-Control header from options like max-age, no-cache, public, private and immutable, with a plain-English explanation.
Last reviewed by the Radiatus Cloud team
Build an HTTP Cache-Control header from caching directives.
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Build a Cache-Control header
The Cache-Control header tells browsers and intermediate caches how to store and reuse a response, and getting it right is key to fast, correct web applications. This builder assembles a valid header from the directives you select: visibility with public or private, a freshness lifetime with max-age, shared-cache lifetime with s-maxage, and behaviour flags such as no-store, no-cache, must-revalidate, immutable and stale-while-revalidate. It also explains in plain English what the resulting header means.
Selecting no-store produces a header on its own, since it overrides the others by forbidding any caching.
Caching done right
Good caching dramatically improves performance and reduces server load, but mistakes cause either stale content or missed caching opportunities. Static assets with hashed file names are often served with a long max-age and immutable, while dynamic pages use no-cache or short lifetimes. Content delivery networks respect s-maxage separately from the browser's max-age.
The plain-English explanation helps you confirm the header does what you intend before deploying it. All header building happens locally in your browser.
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Frequently Asked Questions
What is the difference between no-cache and no-store?
no-store forbids keeping any copy at all, while no-cache allows storing a copy but requires revalidation with the server before each reuse.
When should I use immutable?
Use immutable for versioned static assets whose contents never change, such as files with a hash in the name, so browsers skip revalidation while the response is fresh.
What does max-age control?
It sets how many seconds the response is considered fresh. After that, the cache must revalidate or refetch it.
How is s-maxage different from max-age?
s-maxage applies only to shared caches like CDNs and overrides max-age for them, letting you cache longer on a CDN than in the browser.
What is public versus private?
public lets any cache, including shared ones, store the response, while private restricts storage to the user\'s own browser.
Privacy & Security
Everything runs in your browser; nothing is uploaded.
How to Use
Choose caching directives and a max-age to build the header.
Disclaimer: This tool is provided "as is" without warranty of any kind. Results are for educational and utility purposes.
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