Thursday, August 09, 2007

Grade your website's performance with YSlow

One of the better tools for web developers that exists today is FireBug, a free extension for FireFox. FireBug enables web developers to quickly inspect CSS rules, analyze document structure, and debug JavaScript errors. If you haven't added it to your web development toolbox yet, then do it now. But this post is not not about FireBug, it's about a new tool from Yahoo! called YSlow that extends FireBug (an extension extension?) with incredible performance optimization tools.

YSlow integrates directly into FireBug and when activated it grades the active web page based on Yahoo!'s thirteen simple rules for speeding up your website (another excellent resource). The results of the scan are conveniently presented with a list of scoring metrics, induvidual grades for each metric, details for improving each grade, and direct links to Yahoo!'s resources on performance improvement. I don't think there is any other free tool that exists that makes it this easy to identify easy site performance improvement opportunities.

Clearly, some of the metrics are better suited for larger sites (such as measuring your use of content delivery networks for static content), but for the most part the tips are very helpful. If nothing else, the tool's Stats and Components tabs will help you analyze the total size of your page (pre- and post-cache), the expiration date of your static content, and the size of your cookies- all good things to know when you're trying to optimize an application.

I've got to to give credit to Adam Kinney for blogging this first and bringing it to my attention. Do yourself a favor and download this free tool now and start optimizing your web applications today. With any luck a lot of hard work, maybe you too can earn Google's near perfect score of 99.