Split test developer for hire
Split test, A/B test, experiment: three names for the same build. I write the client-side code that makes a split test run on a live site, on whichever platform you use, and I make sure the traffic split your analytics reports is the one the platform actually served. Seven years, 500+ builds, UK and US hours.
Available to hire now
Direct briefs or overflow build capacity for CRO teams, with a reply within one UK business day.
What a split test build includes
- Variation code that survives the host site. Single-page apps that never re-trigger the platform snippet, elements that render late, React inputs that wipe injected values. Each has a pattern, and each pattern is in the field notes below.
- Redirect handling for split URL tests. Query strings, UTM parameters and session state carried across the redirect, with no flash of the original page first.
- Tracking that agrees with the platform. GA4, Tealium or the data layer, wired so the split in your analytics matches the split in your testing tool. Sample ratio mismatch is a build bug before it is a stats problem.
- Anti-flicker that hides the element, not the page. The control never flashes and Core Web Vitals stay inside budget.
- QA and a clean revert. Cross-browser, cross-device, one revision round, and a handover the in-house team can read.
Platforms I build on
Each platform has its own page on how the builds work:
Split tests I've shipped
- Self-configuring cost comparison on HomeServe PDPs: +13.6% conversion, +53.5% revenue (Webtrends Optimize)
- Radiator Super SKU on Screwfix PDPs: +13.9% conversion across three runs (Optimizely)
- Trustpilot reviews on a Red Cross PLP: +15.04% conversion (VWO)
- Add-to-bag interstitial CTA on Screwfix: +10% conversion (Optimizely)
- Most-relevant USPs on Screwfix: +4.15% conversion, rolled out to 100% (Optimizely)
- Quote-step redesign shipped client-side on a React funnel (Convert)
Field notes
The failures that come up building client-side split tests, each with the fix and the code:
- Sample ratio mismatch in SPA experiments: why GA4 and the platform disagree
- Why your experiment stops firing on SPA route changes
- Stop A/B test flicker without tanking Core Web Vitals
How pricing works
Submit a brief and you get an hour estimate back within one UK business day, with a total you approve before any work starts. Regular volume earns a discounted rate, and there is no lock-in: one-off builds are as welcome as a weekly commitment.
Hire a split test developer
For split test and A/B test builds, overflow capacity for a CRO or experimentation team, or to talk through a specific test. I reply within one UK business day.
Agencies contract and invoice Arafatcro Ltd, a UK limited company registered in England & Wales, on standard supplier terms. Company no. 17325504, verifiable on Companies House.