CSS compression

CSS compression enables to reduce drastically the size of the exchanged data between the server and the browser.

Steps can be enabled in the Backend as follows:

  1. In the module “Install” > “All configuration”, set compression level between 1 and 9, where 1 is least compression and 9 is greatest compression. Suggested and most optimal value is 5.

    $GLOBALS['TYPO3_CONF_VARS']['BE']['compressionLevel'] = 5;
  2. In a .htaccessfile or in virtual host add some configuration provided by file misc/advanced_htaccess.

    <FilesMatch "\.js\.gzip$">
                 AddType "text/javascript" .gzip
         <FilesMatch "\.css\.gzip$">
                 AddType "text/css" .gzip
         AddEncoding gzip .gzip

Followingthose 2 steps will generate a compressed file and therefore add a “gzip” suffix to the file.


Itmay happen that the browser does not support GZIP compression for some reason. Typically, it can be behind a proxy server which does not support GZIP headers. In this case, the compressor will detect it and send the un-compressed files.