Responsive testing tools

Sizzy Tools

Practical public tools and checklists for testing responsive layouts, viewport ranges, and release readiness.

Responsive testing guides

Short references for viewport sizes, breakpoint audits, and visual regression passes.

What Is a Browser for Web Developers?

Why developers are switching from Chrome to dedicated development browsers, what a dev browser actually does, and when it's worth it.

How to Test Responsive Design on Multiple Devices at Once

A practical workflow for testing responsive layouts on every device simultaneously - without buying hardware or juggling browser windows.

Polypane vs Sizzy vs Responsively: An Honest Comparison

A straight comparison of the three main multi-device development browsers - strengths, weaknesses, and which one fits your workflow.

Chrome DevTools Device Mode: 7 Limitations to Know

Chrome's device mode is useful but not the full story. Here's where its emulation differs from reality and how to close the gaps.

How to Debug Media Queries Faster

A systematic workflow for finding and fixing media query bugs - from locating the breaking width to verifying the fix on every breakpoint.

How to Test PWAs Across Devices

Progressive web apps fail in device-specific ways. A workflow for testing installability, offline behavior, and viewport handling across devices.

Responsive Viewport Sizes

A practical viewport size reference for testing mobile, tablet, and desktop layouts before release.

Responsive Visual Regression Checklist

A release checklist for comparing responsive screenshots and catching layout regressions across breakpoints.

iPhone Viewport Sizes

Common iPhone CSS viewport widths and a practical way to choose iPhone test sizes for responsive QA.

Android Viewport Sizes

Common Android viewport widths and QA notes for testing responsive layouts across varied mobile devices.

Responsive Breakpoint Checklist

A practical checklist for auditing CSS breakpoints and validating layout transitions before shipping.