Responsive Testing

Responsive Testing

After a UI change, verify the app looks correct at all standard breakpoints.

Viewports to Test

Workflow

1. Navigate to the Page

Use browser_navigate to open the target URL (usually http://localhost:3000 or whatever the dev server is running on).

2. Test Each Viewport

For each viewport size:

1. Resize the viewport using browser_navigate with viewport parameters, or use browser_snapshot to inspect the layout 2. Take a screenshot with browser_take_screenshot 3. Check browser_snapshot for the aria tree — look for:

• Content overflowing or hidden behind other elements
• Navigation that should collapse into a hamburger menu
• Text that's too small to read
• Buttons/links too close together (touch target issues)
• Horizontal scrollbars that shouldn't exist

3. Check for Common Breakage

• Overflow: Elements wider than the viewport causing horizontal scroll
• Collapsed layout: Flex/grid items that should stack on mobile but don't
• Hidden content: Elements that disappear at certain sizes without a menu toggle
• Font scaling: Text that's readable on desktop but tiny on mobile
• Fixed positioning: Modals, toasts, or sticky headers that break on small screens
• Images: Oversized images that don't scale down

4. Report

Responsive Test Results:
  375px (mobile):  PASS — layout stacks correctly
  428px (mobile):  PASS
  768px (tablet):  WARN — nav items overlap, need hamburger menu
  1280px (desktop): PASS
  1536px (ultrawide): WARN — content not centered, stretched too wide

Fix any issues found, then re-test the affected viewports.