ScreenSync
Preview any website across multiple screen sizes side by side. Built for designers and developers who care about responsive design.
What ScreenSync can do
Multi Device Preview
See your website on desktop, tablet, and mobile screens all at the same time without resizing your browser.
Side by Side View
Compare how your site looks across different breakpoints in a single glance.
Custom Sizes
Add your own custom screen dimensions. Test against any device resolution you need.
Real Time Sync
Scroll, click, and interact on one screen and watch all previews update simultaneously.
Responsive Testing
Instantly test media queries and breakpoints without manually dragging your browser window.
No Data Collection
Everything runs locally in your browser. Your URLs and browsing data never leave your machine.
Up and running in seconds
Open any website
Navigate to the site you want to test in your browser.
Click ScreenSync
The extension opens a multi viewport preview with your site loaded across different screen sizes.
Test and compare
Interact with the previews, adjust sizes, and verify your responsive design works perfectly.
Ready to try ScreenSync?
Free to use. No signup needed. Just install and go.