Responsive Tester — Mobile View by BugCapture

Test any website across mobile, tablet, desktop and custom viewport sizes. Use Mobile View by BugCapture to preview responsive layouts, test breakpoints, compare screen sizes and catch responsive UI issues without repeatedly resizing your browser. The device frames are drawn on top of the page you are already on, so the desktop layout and the mobile one are in front of you at the same time. WHY THIS ONE It loads sites that block being framed. Most serious web apps set X-Frame-Options or a frame-ancestors policy, and the popular responsive extensions simply fail to load them. This one does not. Your login carries in. The preview runs on the page you are already on, so the frames are same-origin and your session is already there — no signing in again, in every frame. It works on http://localhost. Where front-end developers actually work. It tells you what it cannot emulate. A Fidelity panel names, row by row, which signals are real and which are faked — pixel ratio, pointer type, safe area, and the rendering engine. No emulator on Chromium reproduces iOS Safari, and this one says so instead of drawing a convincing phone and staying quiet. It does not randomly stop working. All state is persisted, so the extension survives Chrome idling its service worker. WHAT IS IN IT • 32 screen sizes — iPhone, Android, tablet, foldable and desktop — plus "+ Custom size" for a viewport of your own • Up to 5 frames on screen at once, arranged as a row, a grid or a stack • Rotate any frame to landscape • Drag a frame's edge to resize it live, and watch the page reflow under your hand • Zoom from 25% to 125% • Sync — one scroll, click or keystroke replayed into every frame • Focus — fit every frame on screen and dim the page behind them • Drawn browser bars, so a fixed header is measured against the room a real phone actually leaves for it • A live dimension readout, and the CSS breakpoint band each frame sits in — "at md 768", "above md 768" • Keep open after reload — optional, granted per site from a click, for the current browser session only • Four themes, fourteen languages • Alt+Shift+M opens and closes it on any tab PRIVACY Free, no account, and nothing leaves your browser in this version. No analytics, no tracking, no server — the extension makes no network requests of its own at all. Device names identify screen sizes only. Not affiliated with, endorsed by, or sponsored by Apple, Google, Samsung or any device maker.