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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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