There are different testing tools for responsive design that are based on specific viewports. Given that nowadays we have thousands of devices and almost infinite combinations of screen sizes, those testing tools are limited, since they don’t show your design in all those different random viewports.
Ish is a different responsive design testing tool, it’s not based on predefined viewports, it allows you to test your design on general ranges. As Brad Frost said,
“It’s our jobs as web designers to make sure our interfaces look and function across all screen sizes, and ish. is here to help.”
These are the modes included in this tool:
My favorite. It’s a responsive design stress test. The image above is a capture of that mode.
It starts with the small screen and gradually expands, so you determine breakpoints.
It allows you to manually change the value of the viewport to any screen size, and use the up and down arrow keys to fine tune those dimensions.
Manual Resize mode
It allows you to manually resize the screen without resizing your entire browser window.
It selects a random viewport size.
Small, medium and large modes
It randomly selects a small, medium or large viewport size, instead of specific dimensions.