How long do browsers cache HTTP 301s

Question

I am debugging a problem with a HTTP 301 Permanent Redirect  After a quick test  it seems that Safari clears its cache of 301s when it is restarted  but Firefox does not   When do IE  Chrome  Firefox and Safari clear their cache of 301s   UPDATE  For example  if I want to redirect example1 com to example2 com  but I accidentally set it to redirect to example3 com  that is a problem  I can correct the mistake  but anyone who has visited example1 com in the meantime will have cached the incorrect redirect to example3 com  and so they will not be able to reach either example1 com or example2 com until their cache is cleared  Upon investigation  I find that there were no Cache-Control and Expires headers set  The headers for the incorrect 301 response would have been like this   HTTP 1 1 301 Moved Permanently Date  Wed  27 Feb 2013 12 05 53 GMT Server  Apache 2 2 21  Unix  DAV 2 PHP 5 3 8 X-Powered-By  PHP 5 3 8 Location  http   example3 com  Content-Type  text html   My own tests show that    IE7  IE8  Android 2 3 4 do not cache at all  Firefox 18 0 2  Safari 5 1 7  on Windows 7   and Opera 12 14 all cache  and clear the cache on browser restart  IE10 and Chrome 25 cache  but do not clear on browser restart  so when will they clear

User · Answer

I have simple solution that worked on all major browser  latest version   includes IE  Chrome and FF   Ctrl   Shift   Del -   Chrome  Select  Browsing History  and  Cache     IE  I leave default option  Temporary Internet files and website files    Cookies and website data    History  FF   Browsing and Download history    Cache   Click  Delete  Close and reopen your browser  It should work

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To solve the issue for a localhost address I changed the port number the site ran under  This worked on Chrome version 73 0 3683 86

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Make the user submit a post form on that url and the cached redirect is gone      lt body onload  document forms 0  submit    gt   lt form action  https   forum pirati cz unreadposts html  method  post  gt       lt input type  submit  value  fix    gt   lt  form gt   lt  body gt

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From Chrome 71  To clear a permanent redirect  go to chrome   settings clearBrowserData and from there only clearing  cached images and files  cleared the redirect   Chrome 48-70  Go to chrome   net-internals  On the right of the top red status bar  click on the down arrow   to open the drop-down menu  and under the  Tools  group  choose  Clear cache    As of version 48  this was the only thing that worked for me to clear a cached 301

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An answer that helps those who desperately want to get rid of the redirect cache    Chrome caches the 301 redirect infinitely  in the local disk cache   To clear this cache    open your DevTools  press F12  on the Network tab check the  Disable cache  checkbox keep DevTools open and reload the page  press F5    When everything is okay  you can uncheck  Disable cache  and everything will continue to work as expected

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I will post answer that helped me   go to url     chrome   settings clearBrowserData   it should invoke popup and then     select only  cached images and files  select time box   from beginning

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As the other answers show  Caching may be indefinetly in browser  This is extremely dangerous  So don t do it  At least add cache headers  In htaccess I always do it this way with no caching at all   lt IfModule mod rewrite c gt    RewriteCond   HTTP HOST    www    example  com   NC      The E nocache 1 sets the environment variable nocache to the value of one   RewriteRule         https   www example org  1  L R 301 E nocache 1   lt  IfModule gt     lt IfModule mod headers c gt       Set the response header if the  quot nocache quot  environment variable is set      in the RewriteRule above    Header always set Cache-Control  quot no-store  no-cache  must-revalidate quot  env nocache       Set Expires too       Header always set Expires  quot Thu  01 Jan 1970 00 00 00 GMT quot  env nocache  lt  IfModule gt   Edit  If you didn t had no caching of 301 redirects in the past  you must redirect back to the source from the target  Example  If you had this RewriteRule  my-source  my-target  L R 301   You need to put this   RewriteRule  my-source  my-target  L R 301  RewriteRule  my-target  my-source  L R 301

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301 is a cacheable response per HTTP RFC and browsers will cache it depending on the HTTP caching headers you have on the response  Use FireBug or Charles to examine response headers to know the exact duration the response will be cached for   If you would like to control the caching duration  you can use the the HTTP response headers Cache-Control and Expires to do the same  Alternatively  if you don t want to cache the 301 response at all  use the following headers   Cache-Control  no-store  no-cache  must-revalidate Expires  Thu  01 Jan 1970 00 00 00 GMT

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In the absense of cache control directives that specify otherwise  a 301 redirect defaults to being cached without any expiry date  That is  it will remain cached for as long as the browser s cache can accommodate it   It will be removed from the cache if you manually clear the cache  or if the cache entries are purged to make room for new ones  You can verify this at least in Firefox by going to about cache and finding it under disk cache   It works this way in other browsers including Chrome and the Chromium based Edge  though they don t have an about cache for inspecting the cache  In all browsers it is still possible to override this default behavior using caching directives  as described below  If you don t want the redirect to be cached This indefinite caching is only the default caching by these browsers in the absence of headers that specify otherwise   The logic is that you are specifying a  quot permanent quot  redirect and not giving them any other caching instructions  so they ll treat it as if you wanted it indefinitely cached  The browsers still honor the Cache-Control and Expires headers like with any other response  if they are specified  You can add headers such as Cache-Control  max-age 3600 or Expires  Thu  01 Dec 2014 16 00 00 GMT to your 301 redirects   You could even add Cache-Control  no-cache so it won t be cached permanently by the browser or Cache-Control  no-store so it can t even be stored in temporary storage by the browser  Though  if you don t want your redirect to be permanent  it may be a better option to use a 302 or 307 redirect   Issuing a 301 redirect but marking it as non-cacheable is going against the spirit of what a 301 redirect is for  even though it is technically valid   YMMV  and you may find edge cases where it makes sense for a  quot permanent quot  redirect to have a time limit   Note that 302 and 307 redirects aren t cached by default by browsers  If you previously issued a 301 redirect but want to un-do that If people still have the cached 301 redirect in their browser they will continue to be taken to the target page regardless of whether the source page still has the redirect in place   Your options for fixing this include   A simple solution is to issue another redirect back again  If the browser is directed back to a same URL a second time during a redirect  it should fetch it from the origin again instead of redirecting again from cache  in an attempt to avoid a redirect loop   Comments on this answer indicate this now works in all major browsers - but there may be some minor browsers where it doesn t   If you don t have control over the site where the previous redirect target went to  then you are out of luck   Try and beg the site owner to redirect back to you    Prevention is better than cure - avoid a 301 redirect if you are not sure you want to permanently de-commission the old URL

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Test your redirects using incognito InPrivate mode so when you close the browser it will flush that cache and reopening the window will not contain the cache

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There is a very simple way to remove browser cache for http redirects e g  301  307 etc   You can open network panel in developer console in chrome  Select the network call  Right click on it and then click on Clear Browser Cache to remove the cached redirection

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For testing purposes  to avoid cached redirects   people can open NEW PRIVATE WINDOW   click CTRL SHIFT N  if you use Mozilla  use P

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Confirmed   make the user submit a post request to the affected url and the cached redirect is forgotten   A quick win would be to enter this in the browser console if you can   fetch  example com affected link    method   post    then      gt       Useful if you know the affected browser  especially during development    Alternatively  if you have access to the previous 301 redirect page  then you can add this script to the page and anytime it is visited  the cached 301 will be forgotten

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On the latest Google Chrome Version 79  you can use the chrome   net-internals and select on DNS from the left panel  then tap the Clear host cache button

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as answer of  thomasrutter      If you previously issued a 301 redirect but want to un-do that      If people still have the cached 301 redirect in their browser they will  continue to be taken to the target page regardless of whether the source page  still has the redirect in place  Your options for fixing this include            The simplest and best solution is to issue another 301 redirect back again           The browser will realise it is being directed back to what it previously thought was a decommissioned URL  and this should cause it re-fetch that URL again to confirm that the old redirect isn t still there           If you don t have control over the site where the previous redirect target went to  then you are outta luck  Try and beg the site owner to redirect back to you       In fact  this means    a com  301  to  b com delete a com  s 301  add b com  301 to a com   Then it works

[http] How long do browsers cache HTTP 301s?

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