Like all good engineers, web developers need to build up a set of tools to do a high-quality job. This appendix describes the tools I recommend for analyzing and improving web site performance. The tools are grouped into the following sections:
When I sit down to analyze a web site, I start by looking at the HTTP requests for the web page in question. This makes it possible to identify the slow parts of the page. A packet sniffer that is handy and easy to use is the first tool to add to your kit. The tools included in this category are HttpWatch, Firebug Net Panel, AOL Pagetest, VRTA, IBM Page Detailer, Web Inspector Resources Panel, Fiddler, Charles, and Wireshark.
Performance analyzers evaluate a given web page against a set of performance best practices. As I will explain, they vary a great deal in what they measure. This section describes YSlow, AOL Pagetest, VRTA, and neXpert.
This section includes a grab bag of tools I use regularly: Hammerhead, Smush.it, Cuzillion, and UA Profiler.
Every web developer working on performance needs to look at how his web pages ...