Vermillion

Vermillion is the technical partner subscription app operators trust to build and scale their products. We work with growth marketers, portfolio builders, and indie app founders who understand users and revenue but need a senior engineering team they can rely on for years, not months. We specialize in React Native apps with deep expertise in subscription monetization, paywall optimization, and the RevenueCat/Superwall stack. Our longest client partnership spans 4+ years, we became their entire engineering backbone while they scaled to $750K/month in subscription revenue. What We Do: React Native mobile app development, subscription monetization strategy and implementation, paywall A/B testing and optimization, architecture design for scale and acquisition readiness, fractional CTO advisory for technical decision-making. Who We Work With: Subscription app operators and portfolio builders, growth marketers building app businesses, indie app founders scaling past product-market fit, companies preparing for acquisition or due diligence. Why Clients Stay: We've seen 50+ subscription apps and know what converts. We've been through technical due diligence and know what acquirers look for. Our clients don't churn because we're not project-based, we're the engineering team they never have to replace. Our client's have raised over 27 million dollars in funding. Founded by Ken Vermeille, a developer with 15+ years of full-stack experience and deep mobile monetization expertise.