Dual Mobile Viewer

Desktop and mobile side by side — one click

Stop resizing windows and faking mobile in DevTools. Dual Mobile Viewer splits your screen 50:50: your current page stays on the left, and a true mobile simulation opens on the right — fixed device width and mobile User-Agent included.

A Chrome extension that snaps the active window to the left half, opens a mobile-simulated window on the right, and lets you pick presets like iPhone 15 Pro or Galaxy S24.

Support

Overview

Core features (MVP)

F1 — One-click 50:50 split

Tap “Split view” in the popup. The active window moves to the left 50% of your monitor; a new window fills the right 50% — no manual dragging.

Uses chrome.system.display.getInfo() for workArea dimensions
Left window: chrome.windows.update() on the current window
Right window: chrome.windows.create() at the correct position and size

F2 — Real mobile simulation (not just narrow width)

The right window is forced to behave like a phone: fixed CSS viewport width and mobile User-Agent on network requests.

Device width locked to preset CSS resolution (e.g. 393px for iPhone 15 Pro)
declarativeNetRequest rewrites User-Agent so sites serve mobile pages (e.g. m.example.com)
Same URL as the left tab — compare desktop vs mobile instantly

F3 — Device presets

iOS: iPhone 15 Pro, iPhone SE
Android: Galaxy S24
Tablet: iPad Air
Default: iPhone 15 Pro

Design philosophy

MVP focuses on a clean, practical web view — maximum readable area for responsive QA. Optional device bezel chrome may come later as a toggle for demos and screenshots.

Technical stack

Chrome Extension Manifest V3
Tailwind CSS popup UI
Permissions: windows, tabs, declarativeNetRequest
No external server — browser APIs only

Flow

User flow

From icon click to split view in four steps:

Click the extension icon — lightweight popup opens
Choose a device preset from the dropdown (default: iPhone 15 Pro)
Tap “Split view” — popup closes
Left: desktop page · Right: mobile-simulated window with the same URL

Users

Who it's for

Frontend developers testing responsive breakpoints
Web publishers checking mobile layouts
Product managers and marketers reviewing cross-device UX

Privacy

Reads the active tab URL only when you run split view
User-Agent rules apply only to the right-hand window you create
No browsing data sent to developer servers

Dual Mobile Viewer exists for one job: cut cross-device testing from minutes to one click. Install, pick a device, split — done.

URL

Chrome Web Store URLs

Store listing

Visitors are redirected by country (KR/JP) or browser language to /dualmobile/en, /ko, or /ja.

Homepage URL: https://www.eajiai.com/dualmobile/
Support URL: https://www.eajiai.com/dualmobile/support
Privacy policy URL: https://www.eajiai.com/dualmobile/privacy