Responsive Viewer by Pixellize

Preview any website in multiple screen sizes simultaneously. Built by Pixellize.

Responsive Viewer by Pixellize Responsive Viewer by Pixellize makes it easy to check how a website looks on different screen sizes without constantly resizing your browser. Whether you're working on a landing page, building a new website, or fixing a responsive layout, you can preview mobile, tablet, laptop, and desktop screens side by side in one place. Preview Multiple Screen Sizes at Once Open any website, click the Responsive Viewer extension icon, and the viewer launches with the current page loaded across your selected screen sizes. All previews stay in sync, making it easier to spot layout issues, check breakpoints, and see how your design adapts to different devices. You can also enter another URL directly in the viewer whenever you need to test a different website. Organize Your Workspace with Custom Tabs Keep your testing workflow organized with tabs you can name and customize. Create separate setups for mobile screens, desktop layouts, or your complete device collection, then switch between them whenever you need. The Screens panel lets you add, remove, and rearrange device previews to suit your workflow. Create Your Own Screen Sizes Along with built-in presets for popular phones, tablets, and desktop resolutions, Responsive Viewer lets you create custom screen sizes to match your exact testing needs. Set your preferred width and height, or leave the height empty to use the default of 500 px. Your custom screen sizes are saved and remain available across all your tabs. Test Design Changes with the Live CSS Editor Need to check a CSS fix without editing your website's source code? Use the built-in Live CSS Editor to apply custom styles across your preview frames in real time, without reloading the pages. It includes CSS autocomplete for properties and values, support for `!important`, automatic indentation, closing braces, and line numbers. Close the editor sidebar to remove the injected styles and return to the original page appearance. Focus on One Device with Expanded Preview Sometimes you need a closer look at a particular screen. Simply click the expand icon on any preview to bring it into focus across the canvas. The frame scales to fit the available space while preserving its exact device width, so you can inspect the layout more comfortably. Click the icon again to return to your multi-device workspace. Works with Websites That Restrict Iframes Some websites block standard iframe embedding through their security headers. Responsive Viewer is designed to work around these restrictions, allowing you to preview websites that ordinary iframe-based tools may not load. Actual compatibility can still depend on the website and browser security policies. Your zoom level and custom device configurations are saved between sessions, so you can pick up where you left off without setting everything up again. Responsive Viewer by Pixellize brings multi-device previews, custom screen configurations, and live CSS testing together in one convenient workspace — helping you build, test, and refine responsive websites with less hassle.