Testing on Mobile Devices with Certyn
Use device emulation to test your web app on iPhone, iPad, Pixel, and Galaxy — without owning any of them.
Most web traffic comes from mobile devices, yet most testing still happens on desktop browsers. Certyn bridges this gap with built-in device emulation — the agent can switch to any mobile viewport mid-session.
How It Works
When you tell the agent to test on a specific device, it uses Chrome DevTools Protocol to:
- Set the viewport to the device's exact screen dimensions
- Change the user agent so the site serves mobile-specific content
- Enable touch emulation for touch-based interactions
- Resize the browser window to match the device width
- Reload the page so all changes take effect
Available Devices
Certyn supports these device presets out of the box:
| Device | Resolution | Type |
|---|---|---|
| iPhone 14 | 390 x 844 | Mobile |
| iPhone 14 Pro Max | 430 x 932 | Mobile |
| Pixel 7 | 412 x 915 | Mobile |
| Galaxy S23 | 360 x 780 | Mobile |
| iPad Air | 820 x 1180 | Tablet |
| Desktop 1080p | 1920 x 1080 | Desktop |
What to Test
Mobile testing with Certyn is especially valuable for:
- Navigation menus — hamburger menus, slide-out drawers, bottom nav bars
- Forms — input fields, keyboards, date pickers on small screens
- Tables and data — horizontal scrolling, responsive layouts
- Touch targets — are buttons large enough to tap?
- Media queries — do breakpoints trigger correctly?
Example Scenarios
Test the checkout flow on iPhone
Simply tell the agent: "Switch to iPhone 14 and complete the checkout process." The agent will emulate the device, navigate through each step, and report any issues it finds.
Compare mobile and desktop layouts
Run two sessions — one on desktop, one on iPhone — with the same test case. The agent will flag any layout differences or broken elements.
Test tablet-specific layouts
iPad Air sits between mobile and desktop breakpoints. Many apps have specific tablet layouts that rarely get tested. The agent handles this automatically.
Tips
- Always test your most critical flows on at least one mobile device
- iPad Air is great for catching "in-between" breakpoint bugs
- The agent resets to desktop when you use the
resetpreset - Device emulation changes the user agent, which can affect server-side rendering