Jim S.

Top 3% on Upwork | Fortune 500 & Inc. 5000 Contractor I ship and rescue consumer apps in React Native and Expo from messy MVPs to stable App Store and Google Play releases with subscriptions, attribution, analytics, and production-ready backends. My own app reached #2 in Greece’s Social Networking chart, and I have 6,600+ hours of proven Upwork delivery. I’ve spent the last decade building consumer products that reached App Store top charts, attracted hundreds of thousands of users, and converted free users into paying subscribers. More importantly, I work across engineering, product, and growth. I understand the complete commercial loop from paid acquisition and attribution through onboarding, pricing, paywalls, retention, and LTV. That means I don’t just execute a feature list. I help determine what is worth building, how it should be measured, and whether it is actually moving the business forward. Recent Results * Built and grew a location-based anonymous social app to 30,000+ users in under two months, reached #2 in Greece’s Social Networking chart, and converted users into paying subscribers * Led the Capacitor → React Native/Expo rebuild of an Inc. 5000 survey platform supporting a 250K+ panel * Built a custom fraud-prevention platform that reduced chargebacks by 40% * Shipped subscriptions, paywalls, notifications, moderation, attribution, and analytics across production iOS and Android apps What I Do Best Mobile Product Engineering * React Native and Expo development, rescue, and performance work * App Store and Google Play releases * Supabase and custom backends using Python/Django, Node.js, and Go * Real-time features, moderation systems, notifications, and internal tools Monetization and Growth * RevenueCat, in-app purchases, subscriptions, and paywalls * Pricing, packaging, free trials, offers, and paywall optimization * Onboarding, referrals, gamification, and retention systems * Attribution and event tracking with Branch, AppsFlyer, Amplitude, and Mixpanel * Meta app-ad measurement and acquisition-to-revenue analysis * CAC, ROAS, LTV, ARPU, trial conversion, retention, and churn * A/B testing, behavioral cohorts, and funnel optimization Platform Architecture * REST APIs, microservices, and scalable backend systems * Supabase, PostgreSQL, GCP, Kubernetes, AWS, and Vercel * Full lifecycle ownership from MVP through production growth Why Clients Work With Me * Founder-level ownership: I question assumptions, push back on low-value work, and focus on the highest-leverage opportunities * Commercial judgment: I connect technical decisions to acquisition, conversion, retention, and revenue * End-to-end execution: I can own mobile, backend, infrastructure, analytics, and releases * Independent delivery: I can take an ambiguous problem, determine what matters, and ship the solution I work best with founders who want more than an implementation-only developer. If your consumer app needs to launch, stabilize, monetize, or grow, send me its current state and biggest bottleneck.