Mobile View & Responsive Tester

Test websites across phone, tablet, laptop, and desktop viewports with synchronized previews, design comparison, and captures.

Mobile View & Responsive Device Viewer helps developers test responsive websites across phones, tablets, laptops, and desktop screens. Open it on the current page to compare up to four device viewports side by side without switching between Chrome DevTools presets. Click the extension icon or use the Chrome context menu to open the current website inside realistic device frames. The responsive device viewer appears over the current tab, so you can check mobile view and desktop breakpoints in one workspace and return to the page when you close it. **Responsive website and mobile view testing** - Compare up to four device previews side by side in resizable panels. - Test phone, tablet, laptop, and desktop layouts at realistic viewport sizes. - Switch device, orientation, zoom level, and reload state independently. - Synchronize scrolling across previews when checking long pages. - Create custom viewport sizes for project-specific breakpoints. **Realistic device previews** - Preview iPhone, Android, iPad, tablet, MacBook, laptop, and desktop layouts. - Use device frames with platform-appropriate status and browser chrome. - See viewport dimensions and resize comparison panels directly. **One-click comparison sets** - Open Phone + Tablet, iOS + Android, or Mobile + Tablet + Laptop comparisons from the toolbar. - Save named device sets for repeated responsive QA. - Reuse custom device configurations from local Chrome storage. **Screenshots and annotations** - Capture the complete multi-device comparison. - Annotate with pen, rectangle, arrow, text, and crop tools. - Copy the result to the clipboard or download it locally. **Privacy-first by design** - No account required. - No backend service. - No analytics, telemetry, or remote logging. - Screenshots, URLs, annotations, and settings never leave your browser. - Preferences, presets, recents, custom devices, and UI state are saved locally in Chrome storage.