Computing & Technology

How to Compress Websites with Gzip Compression

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Compressing your website pages on the server is a great way to improve your site speed overall. One site I manage was six times smaller after I enabled gzip compression.

Most modern browsers support compression of HTML, CSS, and JavaScript files. So if you set up your web server to deliver compressed files the majority of your readers will receive compressed files, greatly improving their delivery speed.

Difficulty: Average

Time Required: 15 minutes

Here's How:

First, make sure that your site isn’t already being compressed by your hosting provider. Some hosting providers automatically compress HTML documents for their customers. To verify, use a tool like GIDZipTest to check your site. If it comes back with "Yes" then you’re done.

Chances are that your pages are not compressed. And in order to compress them you need to have the following:
- Know what server you are running (IIS or Apache or something else)
- Access to your web server configuration
For IIS

If your server is IIS, follow the instructions in Microsoft TechNet document to enable compression.

For Apache

Edit your .htaccess file and add the following lines:

# compress text, HTML, JavaScript, CSS, and XML AddOutputFilterByType DEFLATE text/plain AddOutputFilterByType DEFLATE text/html AddOutputFilterByType DEFLATE text/xml AddOutputFilterByType DEFLATE text/css AddOutputFilterByType DEFLATE application/xml AddOutputFilterByType DEFLATE application/xhtml+xml AddOutputFilterByType DEFLATE application/rss+xml AddOutputFilterByType DEFLATE application/javascript AddOutputFilterByType DEFLATE application/x-javascript # remove browser bugs BrowserMatch ^Mozilla/4 gzip-only-text/html BrowserMatch ^Mozilla/4\.0[678] no-gzip BrowserMatch \bMSIE !no-gzip !gzip-only-text/html Header append Vary User-Agent
After you’ve saved the .htaccess file, test your site again in GIDZipTest. It should come up as compressed.

If It Still Isn’t Compressed

Some virtual hosts don’t always recognize output filters that are loaded in the .htaccess file. If your site isn’t compressed after adding those lines, then you’ll need to add them to the vhosts.conf or httpd.conf file for your site.

Look for your site in the file and find the line that starts <Directory>. Then add the above lines into that section of the conf file, above the </Directory> line. Once you’ve saved the file, you’ll need to reload Apache.

If it still isn’t compressed or you can’t edit the vhosts.conf or httpd.conf files, you’ll need to talk to your hosting provider about turning on compression.