Responsive Preview (by Tiny Design Shop) is a free browser tool that shows any URL at mobile, tablet and desktop widths simultaneously, side by side, with synced scrolling and live iframes, no login or install required.
Free.
Designers and developers wanting a fast, no-install way to sanity-check a live page across breakpoints without opening browser devtools or resizing windows manually.
Works on any live URL, not merely local dev sites, useful for quickly checking a competitor's or reference site's responsive behavior as well as your own work.
View any web page at mobile, tablet, and desktop widths side by side, with synced scrolling and live frames, so layout issues are easy to spot.
