Responsive Viewport Tester

Test how a site looks at different viewport sizes. Save device presets when signed in.

Open the tool Build your ownSign in to save your work and revisit it anywhere.

Test how a website looks at different viewport sizes inside a sandboxed iframe. Preset buttons for popular devices plus a custom mode with drag handles. Sign in to save URL+preset combinations for fast project re-testing.

When to use it

1Quick responsive QA of a deployed site you do not have devtools open for.
2Showing a stakeholder how a site looks across screen sizes.
3Building a checklist of presets for a recurring project.

How it works

1
Enter a URL
Top input. The iframe loads it sized to the chosen viewport.
2
Pick or resize
Click a preset (iPhone, iPad, MacBook, etc.) or use the custom mode with drag handles.
3
Save your set
Sign in to save URL+preset combos. Reload them with one click on your next QA pass.

Frequently asked

Why does some site not load?

Sites that set X-Frame-Options: DENY refuse to be iframed. The tool shows a friendly fallback with an 'open in new tab' link.

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