15 Tips to Speed Up Your Website

After seeing some tweets and analyzing the SEOmoz website, I decided to write some tips and tricks that can decrease pages load time as much as possible. Any search engine wants to provide users a great user experience, just like Google, and a fast site improves overall site quality and increases user satisfaction. Everybody deserves a fast web experience. Some of the following tips are implemented well by SEOmoz, but I will explain them anyway because of their general usefulness.

“Experiments demonstrate that increasing web search latency 100 to 400ms reduces the daily number of searches per user by 0.2% to 0.6%. Furthermore, users do fewer searches the longer they are exposed. For longer delays, the loss of searches persists for a time even after latency returns to previous levels.” Google says.

I will list a variety of factors (+ useful tips from Yahoo and Google) and will use SEOmoz as my example:

Note: Making a backup before starting is necessary!

a) Server

Choosing suitable hosting for your venture is the first step in starting a website. Hosting with a professional configuration can be of big help. Here you can find some good tips about choosing hosting.

1. Leverage browser caching

“Expires headers tell the browser whether a resource on a website needs to be requested from the source or if it can be fetched from the browser’s cache. When you set an expires header for a resource, such as all jpeg images, the browser will store those resources in its cache. The next time the visitor comes back to the page it will load faster, as the browser will already have those images available,” says CJ Patrick in a nice article about how to use expire headers to set caching: Expires Headers for SEO

Unfortunately, it seems that SEOmoz doesn’t use expiration for stylesheets and images.

2. Enable Keep-Alive

“A Keep-Alive signal is often sent at predefined intervals and plays an important role on the Internet. After a signal is sent, if no reply is received, the link is assumed to be down and future data will be routed via another path until the link is up again,” says wikipedia.

In fact, HTTP Keep-Alive allows TCP connections to stay alive and it helps reducing the latency for subsequent requests. So contact your hosting provider and tell them to think twice about this! Most hosting companies disable this feature, (including SEOmoz’s host) because it’s an optional feature (whenever it transfers less than 60 bytes per request).

3. Enable gzip compression

* Image by betterexplained.com

“Gzip is the most popular and effective compression method currently available and generally reduces the response size by about 70%. Approximately 90% of today’s Internet traffic travels through browsers that claim to support gzip,” says Yahoo.

Gzipping reduces the size of the HTTP response and helps to reduce response time. It’s an easy way to reduce page weight. You can enable it by adding the following code to your .htaccess file:

# compress text, html, javascript, css, 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
# Or, compress certain file types by extension:

SetOutputFilter DEFLATE

Or, use the following PHP code at the top of your HTML/PHP file:

Or, simply use plugins for your CMS (like the WP HTTP Compression plugin for WordPress).

SEOmoz uses gzip. However, some external javascripts (AdRoll, Simpli and CloudFront) could reduce transfer size more than 60% by using gzip.

4. Make landing page redirects cacheable

Mobile pages redirect users to a different URL, (for example www.seomoz.org to m.seomoz.org) so making a cacheable redirect can speed up page load time for the next time visitors try to load site. Use a 302 redirect with a cache lifetime of one day. It should include a Vary: User-Agent as well as a Cache-Control: private. This way, only those visitors from mobile devices will redirect.

Since SEOmoz doesn’t support any specific mobile version, it can’t have this problem (someone should take care of the bad behavior of SEOmoz’s website on mobile devices)!

5. Use a CDN

A content delivery network (CDN) is a collection of web servers distributed across multiple locations to deliver content more efficiently to users. The server selected for delivering content to a specific user is typically based on a measure of network proximity. For example, the server with the fewest network hops or the server with the quickest response time is chosen. As you can see in the above image, it loads from different servers, based on the visitor’s region. You can compare CDN hosting with standard web hosting here.

It seems that SEOmoz uses Amazon CloudFront for this functionality and I’ve tried MAXCDN, It’s awesome, too. You can manage your caches and lots of other useful tools in one WordPress using W3 Total Cache.

b) Content elements

Since you don’t have total access to your server, content elements are the most important things that you can manipulate. Let’s start with the most obvious weakness of SEOmoz:

1. Minimize redirects

Sometimes to indicate the new location of a URL, track clicks, connect different parts of a site together or reserve multiple domains, you need to redirect the browser from one URL to another. Redirects trigger an extra HTTP request and add latency. Only keep redirects which are technically necessary and you can’t find any other solution for it. These are Google’s recommendations:

• Never reference URLs in your pages that are known to redirect to other URLs. Your application needs to have a way of updating URL references whenever resources change their location.
• Never require more than one redirect to get to a given resource. For instance, if C is the target page, and there are two different start points, A and B, both A and B should redirect directly to C; A should never redirect intermediately to B.
• Minimize the number of extra domains that issue redirects but don’t actually serve content. Sometimes there is a temptation to redirect from multiple domains in order to reserve name space and catch incorrect user input (misspelled/mistyped URLs). However, if you train users into thinking they can reach your site from multiple URLs, you can wind up in a costly cycle of buying up new domains just to stop cybersquatters from taking over every variant of your name.

This image shows what happens when your browser tries to load SEOmoz.org:

As you can see, the greatest latency is the result of some external redirect chains. SEOmoz is using about 20 redirect chains that slow down the load time about 3000 milliseconds.

2. Remove query strings from static resources

You can’t cache a link with a “?” in its URL even if a Cache-control: public header is present. The question mark acts the same as Ctrl+F5. Use query strings for dynamic resources only. SEOmoz is using two dynamic URLs with “?” because of using KISSmetrics, but 2-3 queries are reasonable 😉

3. Specify a character set

Specify a character set in HTTP headers to speed up browser rendering. This is done by adding a simple piece of code into your header:

Note: Some CMSs use functions for character set (like WordPress with ). I suggest that if you are sure about your character set, write it instead of using PHP functions. It helps to minimize request size, so try to use HTML instead of PHP everywhere that is possible.