Arafat I.

Freelance A/B test developer and CRO developer, 7+ years, 500+ tests shipped on Optimizely, VWO, Convert, Adobe Target, Dynamic Yield and custom builds on React, Next.js and Shopify. I build A/B tests that do not corrupt your data. No flicker, no CLS regressions, no sample ratio mismatch. Most experimentation teams share one bottleneck. Research and design move fast, then winning ideas sit in the build queue. I clear that queue. I take a ticket from hypothesis doc to live test without hand-holding: read the brief, build the variation, QA it across browsers and devices, and check the allocation for sample ratio mismatch before anything goes live. You get a result you can trust. Every build includes: Anti-flicker handling so the variation paints clean A CLS budget so the test does not damage Core Web Vitals Sample ratio mismatch review before launch Cross-browser and device QA One revision round Platforms: Optimizely, Convert, VWO, Adobe Target, AB Tasty, Kameleoon, Dynamic Yield, Monetate, Intelligems and Webtrends Optimize, plus custom JavaScript builds on Shopify, React and Next.js storefronts. Single-page apps are where most test builds break. I handle route-change activation, late-rendering elements, controlled inputs and tracking that survives client-side navigation. I work two ways: as white-label overflow for CRO agencies, invisible to your client, and directly with in-house teams that need senior build hands without adding headcount. UK and US hours. How I work, in public: I write up my builds on my site, arafatcro dot com. Recent pieces cover sample ratio mismatch in single-page app experiments, stopping A/B test flicker without hiding the whole page, and abtestrig, the QA tool I built for test builds.l Send me the brief. You get an honest hour estimate back, and I start when you are ready.