Viewport Lab

Extension Developer Tools3 users

Item media 1 (screenshot) for Viewport Lab

Overview

Compare the current page at exact mobile CSS viewport sizes in a focused view or a six-size grid.

Viewport Lab helps developers and designers spot responsive-layout problems without repeatedly resizing a browser window. Click the toolbar icon to open the current page in a focused mobile viewport. Switch to the shared canvas to compare six common widths at once, or enter another HTTP or HTTPS address. Highlights: • focused single view and six-viewport comparison grid; • eight presets from 320×568 through 430×932 CSS pixels; • shared zoom, wheel or trackpad panning, and fit-to-canvas control; • reload and direct open-page actions; • no analytics, advertising, remote code, or broad website permissions. Viewport Lab compares responsive CSS layout. It does not emulate device hardware, DPR, touch input, network conditions, browser engine, or user agent. Some pages block iframe previews through their own security policy; use Open page when that happens.

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Details

Version
1.0.0
Updated
July 24, 2026
Flag concern
Offered by
sonicxboy.dev
Size
29.66KiB
Languages
2 languages
Developer
Email
vixkosla@proton.me
Non-trader
This developer has not identified itself as a trader. For consumers in the European Union, please note that consumer rights do not apply to contracts between you and this developer.

Privacy

Manage extensions and learn how they're being used in your organization

Viewport Lab has disclosed the following information regarding the collection and usage of your data. More detailed information can be found in the developer's privacy policy.

Viewport Lab handles the following:

Web history

This developer declares that your data is

Not being sold to third parties, outside of the approved use cases
Not being used or transferred for purposes that are unrelated to the item's core functionality
Not being used or transferred to determine creditworthiness or for lending purposes

Support

For help with questions, suggestions, or problems, visit the developer's support site

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Visually inspect element alignment on any webpage. Compare center, left, right, top, and bottom edges with live pixel measurements.

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Preview any page in a real mobile viewport — correct breakpoints, mobile user-agent, one click.

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Be Responsive helps you to build smooth and responsive websites by rendering your website in both desktop and mobile view.

FigShot

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Capture any webpage or element into Figma. Inspect CSS, measure spacing, preview responsive layouts, and copy assets instantly.

Responsive View

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View any webpage at phone, tablet, desktop, or custom sizes in one click — resize, screenshot, compare, or emulate.

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Displays the current viewport dimensions in real-time as you resize the browser window.

Screen Ruler

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Use screen ruler for Chrome measure pixels on screen and as browser plugin. Get pixel ruler extension for website page dimensions.

Instant Mobile Preview - Side Panel View

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View mobile versions of websites side-by-side in Chrome's side panel.

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Page ruler extension to measure elements on web pages. An advanced page ruler tool to measure the size of web elements in pixels.

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Use Mobile View Extension for testing mobile websites with a responsive website checker, a responsive design test, and previews.

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Generate a real responsive preview screenshot of the current web page according to the size of mobile phone/tablet/PC.