Enter a URL to see how it looks on common phones, tablets, and desktops. Switch orientation, test breakpoints, and validate responsive layouts without extra devices.
How to use the Responsive Preview effectively
Paste the URL you want to test and load it in the preview panel. Start with a phone-sized device to check navigation, spacing, and readability, then step up to tablet and desktop sizes. Use the orientation toggle to verify layout changes between portrait and landscape. For precise checks, enter a custom width and height that match your breakpoint strategy. If you are working on multiple breakpoints, switch to multi-device view to compare at a glance. Pay attention to fixed headers, sticky elements, and overflow issues that may only appear at certain widths. Keep notes on where your layout starts to break, then adjust your CSS or component rules accordingly.
Why use an online Responsive Preview?
An online responsive preview tool lets you validate layouts quickly without owning a stack of devices. It is ideal for early design QA, client reviews, and quick regression checks after CSS changes. Because it runs in the browser, you can open it on any machine, share the test URL with teammates, and compare results in real time. It also speeds up development by making breakpoints visible and repeatable. Instead of guessing where the layout shifts, you can simulate common viewports and refine your grid, typography, and spacing with confidence.
Features breakdown
- Preset device sizes for popular phones, tablets, laptops, and desktop monitors.
- Custom viewport input for testing any breakpoint or design spec.
- Portrait and landscape toggles to validate orientation changes.
- Multi-device view for side-by-side comparison of key breakpoints.
- Instant reload for iterative testing of responsive changes.
- Local preview workflow without installing device simulators.
Breakpoint strategy and testing checklist
Do not limit testing to just your main breakpoints; resize between them to catch edge cases. Verify that text wraps cleanly, buttons have adequate tap targets, and images scale without distortion. Check navigation behavior: menus should collapse gracefully and remain reachable. Ensure the layout does not create horizontal scrolling on small devices. Validate that line lengths stay comfortable for reading on desktops. If your design uses cards or grids, confirm that spacing and alignment stay consistent as columns change. This systematic checklist prevents the most common responsive bugs from slipping into production.
FAQ
Q: Is the preview the same as a real device?
A: The preview simulates viewport dimensions, which is accurate for CSS-based layouts. Features tied to device hardware or browser quirks can still differ, so final testing on real devices is recommended.
Q: Why can't some websites load in the preview?
A: Some sites block iframe embedding using X-Frame-Options or Content-Security-Policy headers. This is a security setting on the site itself and cannot be bypassed here.
Q: How do I preview a local development site?
A: Enter your local URL such as localhost:3000 or your LAN address. Make sure the server is running and accessible in the current browser, and configure HTTPS or hostnames if your app requires them.