responsivechecktool.com was born from a simple frustration: testing website responsiveness shouldn't require expensive software or complicated setups. We built the responsive test tool we always wished existed โ fast, private, and completely free. Whether you need a quick mobile friendly test online or want to check how your layout looks across every breakpoint, we've got you covered.
We believe that every developer โ whether a solo freelancer or part of a large agency โ deserves access to professional-grade tooling without paywalls, subscriptions, or privacy compromises. Responsive Test Tool is our commitment to that belief.
Our mission is simple: make website screen size checking instant, private, and accessible to everyone. No sign-ups, no data collection, no nonsense. Need to test your website on iPhone screen sizes or check CSS breakpoints online? Just open the tool and test โ no installation required.
Every second counts when you're in flow. Our tool loads instantly and previews update in real time as you type.
Your URLs and test data never leave your browser. We don't log, track, or store anything about what you test.
No premium tiers, no usage limits, no paywalls. Every feature is available to everyone, always.
These aren't just words on a page โ they're the principles every decision we make is filtered through.
Responsive Test Tool is a fully client-side application. When you enter a URL, we load it inside a sandboxed iframe that can be resized to simulate different screen widths and device types. Everything happens in your browser.
We use modern browser APIs to simulate device characteristics including viewport dimensions, pixel density, and touch event support. Our preset library covers popular devices from smartphones to ultra-wide monitors, and you can also enter any custom dimensions you need.
Privacy isn't a feature we added โ it's the foundation we built on. From day one, we made architectural decisions that ensure your data stays yours.
Our advertising is purely contextual โ ads are selected based on the page content, not your browsing history or personal profile. We use no third-party tracking pixels, no behavioral analytics, and no remarketing audiences.
We're a small team and we read every message we receive. Whether you've found a bug, have a feature idea, or just want to say hi โ we'd love to hear from you.
Response times are typically within 1โ2 business days. We take feedback seriously and use it to improve the tool for everyone.