Mobile View: Device Emulator & Responsive Tester, developed by Edison Augusthy, is a free, open-source Chrome extension for examining responsive website layouts. It helps developers, designers, and testers identify breakpoint, overflow, navigation, and content issues without repeatedly resizing the browser window or switching between Chrome DevTools presets. No account or subscription is required.

Multi-device preview controls

The extension displays up to four device previews in resizable panels, covering phones, tablets, laptops, and desktops. Users can start with ready-made comparison sets or create custom viewport sizes for specific project requirements. Saved sets, favorites, recent selections, panel rearrangement, and single-viewport viewing make frequently used configurations easier to revisit.

Scrolling, navigation, supported interactions, and matching nested containers can be synchronized across previews. Each panel also has separate controls for device selection, orientation, zoom, and reloading, allowing users to modify one viewport without affecting the others.

Visual feedback and handoffs

Users can capture an individual viewport or the complete comparison, then annotate the image with a pen, rectangles, arrows, text, or cropping tools. A previous screenshot or approved design can also be placed beside or over the live website for closer visual comparison.

For further testing, a locally generated QR code opens the current URL on a physical phone. The extension can also create a structured responsive-fix prompt containing details such as the affected selector, device names, viewport sizes, orientation, page URL, and expected behavior. This prompt can be copied to a coding tool through the clipboard.

Detailed responsive layout checks

Mobile View is suitable for users who regularly examine responsive layouts in Chrome. Its comparison, annotation, and handoff tools cover several parts of the testing process, though separate browsers and physical devices remain necessary for checking browser-engine differences and performance on actual hardware.