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Testing Responsive Design

By November 2, 2012March 5th, 2021Technology

Viewport resizer 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.

The smartest way to share your defined environment of devices and breakpoints directly with your team and client. However, this bookmarklet should not replace a real device simulation. It rather helps you, your team and client testing statuses, transitions, text length etc. throughout different device types.

Viewport Resizer 


  • Full customization
  • Add and customize sizes on the fly
  • Manually orientation toggle by click (portrait | landscape)
  • Automatically device window orientation in “Auto Size” mode (portrait | landscape)
  • Media query support
  • Adapt meta viewport tag from current page
  • Manually page reload
  • Remove toolbar and land on current page
  • Viewport information (size, aspect ratio, orientation and user agent)
  • Vector-based
  • Touch-friendly

Requirements: JavaScript Enabled
License: License Free