Responsive provides the facility to work for online and local. This also have the controls that help you to adjust the width and height of your viewport to find exact breakpoint widths in pixels.
Responsive design Bookmarklet is another excellent tool that find your designs responsive or not. For using this, just drag and drop the bookmarklet above your bookmarks bar find the current page width and height.
Type your site and find the site( width and height) of your websites on every devices like smartphone, tablets, PC and laptops.
Retina Images serves different images based on the device being used by the viewer. Once setup on your website (very simple!) all you have to do is create a high-res version of each image you would like optimised for retina screens and all the work is done for you.
This is another great online tool for responsive design testing. Enter the sites’s URL and also you can select the device on which you you want to test this.
ProtoFluid simplifies the development of fluid layouts, adaptive CSS and responsive design. It builds precise, dynamic viewports in which to test your work. This allows you to quickly effect changes and demonstrate benefits to interested parties.
This is a browser-based tool to test any website’s responsiveness. Just save the bookmarklet, go to the page you want to test, click on your created bookmarklet and check all kinds of screen resolutions of the page.
Responsive.is online tool to responsive design testing.
Responsinator helps website makers quickly get an indication of how their responsive site will look on the most popular devices. It does not precisely replicate how it will look, for accurate testing always test on the real devices.