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QA Fundamentals

The Complete Web Application QA Testing Checklist

9 min readBy RedQA Engineering Team

How to use this checklist

This checklist covers the core areas every web application should be tested against before release. Use it as a minimum bar — not a substitute for risk-based testing, which should be calibrated to your specific application.

1. Functional Testing

  • All user-facing features work as specified
  • Edge cases tested: empty inputs, maximum lengths, invalid formats
  • Error messages are clear and actionable (not just "An error occurred")
  • Form validation works client-side and server-side
  • Multi-step flows complete correctly and handle back-navigation gracefully
  • Confirmation dialogs, modals, and tooltips behave correctly
  • Pagination, sorting, and filtering work correctly with varied data

2. Cross-Browser & Cross-Device Testing

  • Chrome (latest), Firefox (latest), Safari (latest), Edge (latest)
  • iOS Safari on iPhone (latest OS)
  • Chrome on Android
  • Responsive breakpoints: mobile (375px), tablet (768px), desktop (1280px), large (1920px)
  • Touch interactions work correctly on mobile (tap targets ≥48px recommended)

3. Accessibility Testing

  • Run automated scan with axe or RedQA's free scanner
  • All images have meaningful alt text (or alt="" for decorative images)
  • All form inputs have associated labels
  • Keyboard navigation: can complete all flows without a mouse
  • Focus indicators are visible
  • Colour contrast meets 4.5:1 for normal text, 3:1 for large text
  • Page has a logical heading structure (one H1, logical H2/H3 hierarchy)
  • ARIA roles and attributes used correctly

4. Performance Testing

  • Run Lighthouse (Chrome DevTools) — aim for 90+ on Performance
  • Largest Contentful Paint (LCP) < 2.5 seconds
  • Cumulative Layout Shift (CLS) < 0.1
  • First Input Delay (FID) / Interaction to Next Paint (INP) < 200ms
  • Images are compressed and served in WebP format where possible
  • JavaScript bundle size reviewed — no unnecessary large packages

5. API Testing

  • All expected responses return correct HTTP status codes
  • Validation errors return 400 with actionable messages
  • Authentication required endpoints return 401/403 for unauthenticated/unauthorised requests
  • Error responses don't leak internal implementation detail (stack traces, DB errors)
  • Rate limiting is in place on sensitive endpoints
  • Response time for critical endpoints under load

6. Security Basics

  • No sensitive data in URLs (token, password, PII)
  • HTTPS enforced, no mixed content
  • CSRF protection on state-changing requests
  • Input not reflected unescaped into HTML (XSS risk)
  • SQL injection test on all input fields that interact with a database
  • Cookie flags: Secure, HttpOnly, SameSite=Strict/Lax

7. Regression Testing

  • Core user journeys still work after the latest changes
  • Previously reported bugs are confirmed fixed and not re-introduced
  • Automated regression suite runs green

Need help building this testing coverage for your application? Get in touch with RedQA.

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