I worked as Product Designer for 2.9 years on dfndr security, a mobile protection app with over 100M downloads. The main goal was increasing subscriptions for premium plans (Ultra, Pro, and Ads Free). My work focused on conversion optimization through interface customization and visual design. I customized the home interface for campaigns, adjusting buttons and CTAs based on ongoing promotions and seasonal moments. I also designed and tested different layouts for subscription plan screens, experimenting with pricing displays and feature comparisons to improve conversion rates. I created campaign illustrations tied to current events and cultural moments to build emotional connection with users. Based on user research, I localized experiences for different markets—Brazilian users prioritized performance features while US users focused more on privacy and VPN. Throughout this time, I maintained the design system with components and illustration guidelines to ensure consistency across markets. The work resulted in a 15% increase in plan acquisition, measured over one month.