Test Responsive Designs Across All Devices at Once

Responsive Viewer lets you preview your website on multiple device screens simultaneously. Instead of resizing your browser window repeatedly, see how your design looks on iPhones, iPads, MacBooks, and desktops - all at the same time. With synchronized scrolling and real device dimensions, you'll catch responsive design issues faster than ever.

Key Features

Everything you need to test responsive designs efficiently

Multi-Device Preview

View your website on multiple device viewports simultaneously. Compare how layouts, fonts, and images render across phones, tablets, laptops, and desktop screens - all in one view.

40+ Device Presets

Choose from a comprehensive library of real device dimensions including iPhone 15/16 series, Samsung Galaxy S23-S25, Google Pixel 7-9, iPads, MacBooks, and desktop monitors up to 4K.

Synchronized Scrolling

Scroll in any viewport and all other viewports scroll proportionally. Perfect for checking how content aligns across different screen sizes as you navigate through the page.

Portrait & Landscape Modes

Toggle device orientation with one click. Test how your responsive breakpoints handle both portrait and landscape orientations on mobile and tablet devices.

Zoom Controls

Zoom in from 10% to 200% to fit more viewports on screen or inspect details closely. Maintain visual clarity while testing multiple devices simultaneously.

Custom Devices

Create custom device presets with any width and height you need. Save them for quick access when testing specific viewport sizes unique to your project requirements.

URL Navigation

Edit the URL directly in the toolbar to test different pages. All viewports update simultaneously, maintaining sync as you navigate through your site.

Device Categories

Devices are organized into intuitive categories: Phones, Tablets, Laptops, and Desktops. Quickly find the device you need with the built-in search filter.

Persistent Settings

Your device selection, custom devices, scroll sync preference, and dimension display settings are automatically saved and restored across sessions.

Dimension Labels

Each viewport displays its device name and exact pixel dimensions. Toggle dimension labels on or off depending on your workflow preference.

Real Device Viewports

All device presets use actual viewport dimensions from real devices. Test against iPhone 16 Pro Max (440×956), iPad Pro 12.9" (1024×1366), and more.

Keyboard Shortcuts

Press Escape to close the viewer. Use the toolbar for quick zoom adjustments. Efficient keyboard-driven workflow for rapid testing.

Side-by-Side Testing

See all your target devices at once. No more switching between browser sizes or device emulators.

Latest Devices

Updated presets include iPhone 16, Samsung S25, and Pixel 9 series with accurate viewport sizes.

Sync Settings

Toggle scroll sync and dimension labels. Your preferences persist across browser sessions.

Perfect For

📱 Mobile-First Development
🎨 UI/UX Designers
QA Testing
🔧 Responsive Debugging
👥 Client Presentations
📐 Breakpoint Testing