1. Test forms with realistic and invalid inputs
The most dangerous bug on any website is a contact or checkout form that silently fails. A visitor types their inquiry or credit card info, clicks "Submit", and the button just spins indefinitely or does nothing. The visitor assumes the site is broken and leaves for a competitor.
Always submit every form on your site with empty fields, invalid emails, and correct data. Ensure your backend returns clear, friendly error messages instead of raw JSON or silent network errors.
- Verify that loading spinners stop if an API endpoint returns a 500 status code.
- Check that success confirmation messages appear visibly above the fold.
- Test password reset and lead generation forms on both desktop and mobile.
2. Check for unwanted horizontal scrolling on mobile
A website should never wobble or scroll sideways on a phone. Horizontal overflow almost always happens when an image, pricing table, or embed has a fixed pixel width like `width: 600px` without `max-width: 100%`.
On a 375px iPhone screen, a 400px table pushes the entire page layout outward, leaving a frustrating white gap down the right side of the screen.
3. Inspect all navigation and footer links for 404s
During development, team members frequently use temporary placeholder links like `href="#"` or forget to update draft URLs like `/demo-old`. When real customers click these links, they hit frustrating dead ends.
Crawl every anchor tag in your header, mobile drawer, and footer. Pay special attention to legal links, social icons, and secondary documentation pages.
4. Re-test after every deployment
Even a minor CSS tweak or package upgrade can unexpectedly push a button off-screen or break a third-party analytics script. Running a quick automated health scan after each release gives you confidence that yesterday’s fix didn’t cause today’s bug.