Responsive Design Tester

Device:
×
Viewport: 375 × 667 · DPR: 1
Enter a URL and click Preview

Features

🖥️ Device Presets

Quickly switch between iPhone SE, iPhone 12, iPad, iPad Pro, Desktop, Laptop, and Samsung Galaxy viewports with a single click.

↔ Side-by-Side Comparison

Open a second viewport panel to compare two different screen sizes simultaneously in real time.

📐 Custom Dimensions

Enter any custom width and height values. Use the rotate button to instantly swap dimensions for landscape testing.

ℹ Viewport Info

See the current viewport dimensions and your device pixel ratio at a glance to understand how your layout renders.

Frequently Asked Questions

Why do some websites not load in the preview?

Some websites set X-Frame-Options or Content-Security-Policy headers that prevent loading inside iframes. This is a security feature of the target website and cannot be bypassed by this tool. Try testing your own local or staging sites, which typically allow iframe embedding.

How accurate is the device preview?

The preview simulates viewport dimensions and device pixel ratio. It does not emulate browser engines, touch events, or OS-specific rendering behaviors. For pixel-perfect testing, use real devices or browser DevTools device emulation in addition to this tool.

Can I test two viewports at the same time?

Yes. Click the "Side by Side" button to open a second preview panel. Each panel has independent device presets and custom size controls so you can compare any two viewports simultaneously.

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