A 25-Point Checklist for a Mobile-Friendly Website

Mobile usability involves more than fitting a page onto a narrow screen. Use real content and record a pass, fail or not-applicable result for every check. Browser resizing helps with layout; physical phones are still needed for touch and keyboard behaviour.

Checklist

1. Check for horizontal overflow at 360 pixels.
2. Check that the main offer and heading remain readable at 390 pixels.
3. Check the navigation and content layout at 768 pixels.
4. Repeat the main task in landscape orientation.
5. Enlarge text and check that labels and controls remain available.
6. Open and close the mobile menu using touch.
7. Check that keyboard focus remains inside an open menu.
8. Close the menu with Escape and check that focus returns to its trigger.
9. Check that every interactive control has a visible focus indicator.
10. Try adjacent links and buttons with a real finger.
11. Check that the telephone link opens the correct number without making a call.
12. Check the WhatsApp destination and message context without sending a message.
13. Check visible, associated labels on every form field.
14. Check the email keyboard on a physical phone.
15. Try letters and an implausibly short number in the phone field.
16. Try an invalid address in the website URL field.
17. Check that an error includes an explanation rather than colour alone.
18. Check that entered details survive a validation error.
19. Check that the submit button remains reachable with the keyboard open.
20. Check that fixed contact and cookie controls do not cover the form.
21. Check image proportions and layout movement during loading.
22. Measure when the first screen and main action become usable on a slow connection.
23. Check tables, long addresses and unbroken text for overflow.
24. Use an authorised test submission to verify the success screen and notification.
25. Repeat the main task on physical iOS Safari and Android Chrome devices.

Practical example

Ask someone unfamiliar with the business to find a service and send a test enquiry. Record the exact step, expected outcome and observed obstacle. A screenshot alone does not show whether the task can be completed.

Decision standard

Keep layout checks and physical-device checks separate in the record. Do not describe browser resizing as a completed real-device test.