CRX id
nlikakmcjiiilklicpchpckfkncofoii
nlikakmcjiiilklicpchpckfkncofoii
Description from extension meta
Open any page in exact device viewports (locked size), rotate, theme preview, and take clean screenshots.
Image from store
Description from store
🌍 The Story Behind Viewport Lab
Viewport Lab began life as a side-project: Flutter Responsive Tester.
As a Flutter developer, I needed a simple way to lock a page into real device sizes, rotate between orientations, and quickly check how my app responded — all without the hassle of external emulators.
But something unexpected happened.
Frontend devs from other ecosystems (React, Vue, Angular, Svelte, plain HTML/CSS) started using it too. The problem wasn’t just Flutter — it was responsive testing itself.
That’s when the project evolved and got a new name: Viewport Lab.
Because this isn’t just for Flutter anymore — it’s for everyone building for the web.
✨ Key Features
👉 Exact Device Viewports - Open pages in locked mobile, tablet, or desktop sizes - Supports iPhone, iPad, Android, and custom devices - Save, edit, or delete your own devices
👉 Rotation (Portrait & Landscape) - Test both orientations instantly with a single click
👉 Theme Preview (System / Light / Dark) - Emulate OS-level theme preferences Check if your site respects `prefers-color-scheme`, Filter fallback included for stubborn sites
👉 Screenshot Capture -Take clean screenshots (toolbar auto-hides during capture) - Save for bug reports, documentation, or demos
👉Multi-Device Launch - Open multiple viewports side by side - Compare layouts across devices in real-time
👉 Precision Mode (Dev Build) - For advanced developers and testers - Emulate User-Agent strings, DPR, touch, geolocation, network throttling, reduced-motion - Powered by Chrome’s DevTools Protocol
👉Custom Devices Add your own screen sizes - Delete old entries with one click (trash icon) - Lightweight and Fast - No external API calls - No cloud dependency - Works offline
🖼️ Who Uses Viewport Lab?
👉 Flutter Developers
👉 Verify breakpoints in Flutter web apps
👉 Take quick screenshots for stakeholders
👉 Frontend Developers
👉 Test responsive CSS, flex/grid, media queries
👉 Verify design systems across screen widths
👉 UI/UX Designers
👉 Preview mockups and live sites in mobile/tablet frames
👉 Test color schemes with light/dark toggle
👉 QA Testers
👉 Quickly validate responsive bugs without heavy simulators
👉 Export screenshots to bug trackers
👉 Agencies & PMs
👉 Demo websites in “real device” views during client reviews
🎯 Why Use Viewport Lab Over Chrome DevTools?
Chrome DevTools already has “Device Toolbar” — so why Viewport Lab?
✅ Cleaner workflow — no switching panels, just a dedicated viewport window
✅ Screenshot-ready — toolbar hides for pixel-perfect screenshots
✅ Theme emulation — quick light/dark toggles
✅ Multi-window support — view multiple devices side by side
✅ Custom devices — save and reuse your own presets
✅ Lightweight — no console clutter, no inspector overhead
Viewport Lab is built for speed, focus, and convenience.
🔒 Privacy Promise
Viewport Lab is fully local-first:
✅ No tracking
✅ No analytics
✅ No external servers
✅ No data collection
✅ Your websites, screenshots, and test results never leave your browser.
🛠️ Roadmap
Bulk screenshots (export multiple devices in one click)
Companion app for WebKit & Firefox previews via Playwright
Optional cloud testing for Safari/iOS devices
👉 Install Viewport Lab today. Whether you’re building in Flutter, React, Vue, Angular, or plain HTML/CSS, it’s the fastest way to check your responsive designs.