b/HTTP/Caching#fresh_and_stale_based_on_age) response every time â
or if the client already has a new one, just respond ` 304 Not Modified ` .

http

    
    
    Cache-Control: no-cache
    

Most HTTP/1.0 caches don't support ` no-cache ` directives, so historically `
max-age=0 ` was used as a workaround. But only ` max-age=0 ` could cause a [
stale response ](/en-US/docs/Web/HTTP/Caching#fresh_and_stale_based_on_age) to
be reused when caches disconnected from the origin server. ` must-revalidate `
addresses that. That's why the example below is equivalent to ` no-cache ` .

http

    
    
    Cache-Control: max-age=0, must-revalidate
    

But for now, you can simply use ` no-cache ` instead.

###  Clearing an already-stored cache

Unfortunately, there are no cache directives for clearing already-stored
responses from caches.

Imagine that clients/caches store a [ fresh ](/en-
US/docs/Web/HTTP/Caching#fresh_and_stale_based_on_age) response for a path,
with no request flight to the server. There is nothing a server could do to
that path.

Alternatively, ` Clear-Site-Data ` can clear a browser cache for a site. But
be careful: that clears every stored response for a site â and only in
browsers, not for a shared cache.

##  Specifications

Specification  
---  
[ HTTP Caching  
#  field.cache-control  ](https://www.rfc-editor.org/rfc/rfc9111#field.cache-
control)  
[ HTTP Immutable Responses  
#  the-immutable-cache-control-extension
](https://httpwg.org/specs/rfc8246.html#the-immutable-cache-control-extension)  
  
##  Browser compatibility

BCD tables only load in the browser  with JavaScript enabled. Enable
JavaScript to view data.

##  See also

  * [ HTTP caching ](/en-US/docs/Web/HTTP/Caching)
  * [ Caching Tutorial for Web Authors and Webmasters ](https://www.mnot.net/cache_docs/)
  * [ Caching best practices & max-age gotchas ](https://jakearchibald.com/2016/caching-best-practices/)
  * [ Cache-Control for Civilians ](https://csswizardry.com/2019/03/cache-control-for-civilians/)
  * [ RFC 9111 â HTTP Caching ](https://httpwg.org/specs/rfc9111.html)
  * [ RFC 5861 â HTTP Cache-Control Extensions for Stale Content ](https://httpwg.org/specs/rfc5861.html)
  * [ RFC 8246 â HTTP Immutable Responses ](https://httpwg.org/specs/rfc8246.html)

##  Help improve MDN

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