Viewport Lab by Blaise — Responsive Simulator

Preview websites on 19 phone, tablet and laptop screens. Device frames, precise viewport controls and local PNG screenshots.

One website. Every viewport. Viewport Lab brings responsive website testing into a clean, centered device preview. Open a website, choose a screen, and interact with the real page inside a phone, tablet or laptop outline. Start with 19 presets spanning iPhone, Pixel, Samsung Galaxy, iPad and MacBook screen sizes. Rotate the view, add custom dimensions, and see exactly how much screen space is reserved for browser controls. BUILT FOR RESPONSIVE CHECKS • 19 device presets, with links to their dimension sources • Portrait and landscape switching • Centered device outlines with automatic fit or a scrollable 1:1 view • Separate full-screen and usable webpage dimensions • Expanded, compact, full-screen and custom browser-control budgets • Custom screen sizes, pixel density and saved local profiles • Touch-style taps and drag scrolling, or desktop mouse and keyboard input • Light, dark and system color-scheme preferences • Optional Chrome Android user-agent requests for mobile-site checks • Live verification of viewport, screen dimensions and pixel density • Local PNG screenshots at the configured device pixel density YOUR REAL PAGE, IN CHROME The preview stays connected to the original tab, so your page keeps its login, cookies and navigation. No iframe is used to load the website, and the extension does not remove its security headers. LOCAL BY DESIGN No extension account, subscription, analytics or advertising. Website previews, input events and screenshots are processed locally in Chrome. The extension does not upload page content or screenshots to the developer or a capture service. Custom profiles and preferences are saved on your device. The websites you open continue to make their own normal network requests. WHAT THE SIMULATOR DOES Every preset renders through Chromium, including Apple devices. Viewport Lab reproduces screen and CSS viewport sizes; it does not run iOS, Safari, Android hardware or a virtual keyboard. Browser-control heights are adjustable testing assumptions because real browser bars vary by platform, settings and scrolling. Use real devices for final browser-engine, safe-area and performance validation. PERMISSIONS Chrome's debugger permission powers native viewport metrics, touch input, the connected preview and screenshots. Chrome shows its standard debugging notice while a simulation is active. The sidePanel permission hosts the controls, storage saves local settings, and activeTab identifies the website you choose. Close DevTools or disconnect another debugger before starting. Stop the simulator or use Chrome's Cancel button to restore normal browsing. Viewport Lab supports HTTP and HTTPS websites. Chrome internal pages, the Chrome Web Store, protected pages and local file URLs may not be available for simulation. Browser-native file pickers, permission prompts and password-manager menus belong to the original tab; use Open original tab when needed. Support: menniablaise@gmail.com The device names identify testing presets. Viewport Lab is independent and is not affiliated with Apple, Google or Samsung.