Web Based Free Responsive Design Testing Tool: Screenqueri.es
Screenqueri.es is a Pixel Perfect Tool to test your Responsive Design / Media Queries. Select from Pre-defined Screen Resolutions OR Drag Screen Handles To Go With Your Custom Screen Resolutions.
With a valid site URL this responsive design testing tool shows how the design adapts to the screens of various devices.
Responsive HTML Website Testing Tool – http://www.htmlslicemate.com/responsive-design-testing