Page Speed and
YSlow analyse web pages and suggest ways to improve their performance.
Page Speed is an open-source project started at Google to help developers optimize their web pages by applying web performance best practices. It's available for Chrome and Firefox. Page Speed started as an open-source browser extension, and is now deployed in third-party products such as Webpagetest.org, Show Slow and Google Webmaster Tools.
YSlow is from Yahoo. It's also available for Chrome and Firefox. In addition, it's available for Mobile/Bookmarklet and Node.JS (coming soon).
Quote:Yahoo!'s Exceptional Performance team has identified 34 rules that affect web page performance. YSlow's web page analysis is based on the 23 of these 34 rules that are testable. Click each performance rule below to see the details.
Minimize HTTP Requests
Use a Content Delivery Network
Avoid empty src or href
Add an Expires or a Cache-Control Header
Gzip Components
Put StyleSheets at the Top
Put Scripts at the Bottom
Avoid CSS Expressions
Make JavaScript and CSS External
Reduce DNS Lookups
Minify JavaScript and CSS
Avoid Redirects
Remove Duplicate Scripts
Configure ETags
Make AJAX Cacheable
Use GET for AJAX Requests
Reduce the Number of DOM Elements
No 404s
Reduce Cookie Size
Use Cookie-Free Domains for Components
Avoid Filters
Do Not Scale Images in HTML
Make favicon.ico Small and Cacheable
