YSlow - Official Open Source Project WebsitePhantomJS is a headless WebKit with JavaScript API. YSlow for PhantomJS is a command line script that allows page performance analysis from live URLs, unlike YSlow for Command Line (HAR) where a pre-generated HAR file is needed in order to analyze page performance. YSlow for PhantomJS also introduces new output formats for automated test frameworks: TAP (Test Anything Protocol) and JUnit, other fo
