How is this different to inspecting using Google Chrome dev tools, or the Firefox equivalent? I feel like I'm missing something.
Why is everyone is building tools that do the same thing? This is certainly not the only website out that there lets you preview a responsive design.
What does this offer that the responsive mode in Chrome dev tools doesn't?
Something quite similar is implemented on Chrome 50 (dev). I imagine they will integrate (or replace the current one) with that.
Thanks for the share Nick! I usually build similar tooling directly into my styleguides. Would love to check out the code though. Is it up on Github?