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Decision Guide

Best A/B Testing Tool for Mobile Web

Updated December 2026
10 min read
TL;DR

For mobile web testing: Use ExperimentHQ for its tiny script size (<5KB) and mobile preview. Large scripts (100KB+) hurt mobile performance and conversions. Key features: device targeting, mobile preview in editor, and responsive variant design. Always test on real devices, not just browser emulators.

Who this is for

  • Sites with 50%+ mobile traffic
  • E-commerce stores optimizing mobile checkout
  • Teams running mobile-specific experiments

Who this is NOT for

  • Native mobile app testing (use app-specific tools)
  • B2B sites with primarily desktop traffic

Why Mobile Testing is Different

  • • Performance matters more: Mobile networks are slower, heavy scripts kill conversions
  • • Touch vs click: Thumb zones, touch targets, and gesture patterns differ from desktop
  • • Screen real estate: Less space means every pixel matters
  • • Context differs: Mobile users are often distracted, on-the-go

Tool Comparison

ToolPriceMobile PreviewScript SizeVerdict
ExperimentHQ$29/mo<5KBBest Overall
VWO$10,000+/yr~150KBEnterprise
Convert$699/mo~80KBGood mid-market
Optimizely$50,000+/yr~200KBEnterprise only

High-Impact Mobile Tests

Touch target size

Buttons 44x44px minimum, spacing between tappable elements

Mobile navigation

Hamburger vs bottom nav, sticky header behavior

Form optimization

Input types, autofill, keyboard optimization

Above-the-fold content

What shows before scrolling on mobile screens

CTA placement

Fixed bottom CTA vs inline, thumb-zone optimization

Image loading

Lazy loading, image sizes, placeholder strategies

Our Recommendation

For most mobile web testing: Use ExperimentHQ. <5KB script, mobile preview, device targeting.

Critical: Avoid tools with 100KB+ scripts. On mobile, every KB costs conversions.

Pro tip: Always test on real devices. Browser emulators miss touch behavior and real network conditions.

FAQ

Should I run separate tests for mobile and desktop?▼
Often yes. Mobile and desktop users behave differently. A change that wins on desktop might lose on mobile. Use device targeting to run parallel experiments.
How much does script size affect mobile conversions?▼
Significantly. Studies show every 100ms of load time costs 1% of conversions. A 150KB script can add 500ms+ on 3G networks. This is why lightweight tools outperform enterprise solutions on mobile.

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