What to look for in a mobile simulator extension
- Several devices at once. Responsive bugs live between sizes. Seeing a phone and a tablet together saves the most time.
- A real mobile user agent. Without it, sites that detect phones on the server send the desktop version and you test the wrong page.
- Current devices. New iPhones, Galaxy phones and foldables every year. Check how recently the list was updated.
- Sites that block frames. Many extensions show a blank screen for sites that forbid framing. Try your own site before you commit.
- Capture. Screenshots, video and mockups if you demo work to clients or post on social media.
- Privacy and price. Who sees your browsing, whether there are ads, and what the paid plan costs, clearly.
The options compared
| Tool | Type | Devices side by side | Recording | Price |
|---|---|---|---|---|
| PocketView | Extension | Yes, 2 free | MP4 and GIF | Free; Pro planned |
| Mobile simulator, responsive testing tool (Mobile FIRST) | Extension | Yes | WEBM, GIF and MP4 | Free with a paid plan |
| Window Resizer | Extension | No, one size at a time | No | Free |
| Chrome DevTools device mode | Built into Chrome | No, one device | No | Free |
PocketView
36 devices including the newest foldables (iPhone Duo, Galaxy Z Fold8, Z Flip8, Xiaomi 18 Fold) in official colours, sync scroll and clicks, MP4 and GIF recording with touch ripples, Mockup Studio, app mode for PWAs, dark mode and a real user agent per device. No ads, no analytics, no account. The free version shows 2 devices at once.
Mobile simulator, responsive testing tool (Mobile FIRST)
The most installed tool in this category, with a high rating on the Chrome Web Store. Its listing describes 58+ devices, multi-device comparison, custom devices, transparent PNG screenshots, realistic touch scrolling, PWA mode and one-click video capture. A strong choice; compare the device list and the paid plan with your needs.
Responsive Viewer
Shows a site at several screen sizes at once and syncs clicks and scrolling between them. An independent review notes that sites which block framing will not load in it, and that input syncing is more limited than click and scroll syncing.
Window Resizer
Resizes your browser window to preset sizes. Great for checking breakpoints quickly, but it shows one size at a time and does not change the user agent, pixel ratio or touch behaviour, so it is a breakpoint tool rather than a device simulator.
Chrome DevTools device mode
Built in and free, with network and CPU throttling and CSS inspection right beside the page. One device at a time and no device frames. See how to use mobile view in Chrome.
Which one fits you
- You inspect CSS all day: DevTools, plus a simulator for side-by-side checks.
- You only need breakpoint widths: Window Resizer is light and simple.
- You test on the newest phones and foldables, and show your work to clients: PocketView.