At RN42 IT Services, we leverage over seven years of practical experience to create modern, high-quality software that empowers businesses in various sectors, including fintech, healthcare, e-commerce, and B2B platforms. We assist our clients in building, scaling, and maintaining web and mobile applications, with an emphasis on clean architecture, performance enhancement, and outstanding user experience. 🌐 **Frontend Development** *React.js & Next.js Applications:* We specialize in developing modern Single Page Applications (SPAs) and Server-Side Rendered (SSR) websites, prioritizing performance, SEO, and maintainability. Our expertise includes Tailwind CSS, Styled Components, CVA, and Storybook, along with the integration of REST and GraphQL APIs and the creation of atomic and reusable components. *React Native Mobile Apps:* We build cross-platform applications for iOS and Android using React Native and Expo, complemented by advanced state management techniques such as Redux, Redux Saga, and RTK Query. We also integrate Google Maps, geolocation, and offline-first functionality, and manage build processes for APK/IPA deployments, over-the-air updates, and CI/CD pipelines. 🛠️ **Backend Development** *Python & Node.js Services:* We create RESTful APIs and microservices utilizing FastAPI, Django, and NestJS, focusing on high-performance data workflows and integration from multiple sources (like PagSeguro’s B2B ecosystem). We use OpenAPI for clear interface definitions between frontend and backend and employ Docker containerization for scalable deployments. ✅ **Testing & Quality Assurance** *Unit and Integration Testing:* Our approach includes the use of Jest, Cypress, Vitest, and React Testing Library. We ensure code quality through static analysis and monitoring with SonarQube while adhering to Clean Code principles and design patterns. 💡 **UX-Driven Development** *Design Implementation:* We convert Figma designs into pixel-perfect, accessible interfaces. Our user-centric designs, like the frictionless OTP flows created for elderly users in the Lia Example, illustrate our commitment to usability. We also practice collaborative wireframing (such as Trek Design) to align expectations when design sprints are unavailable.