Senior Full-Stack Developer React Native & Nodejs | Short-Term B2B Freelance

Hi there! We are STX Next, a global IT consulting company specializing in customer-focused software services. Join a group of 500 professionals dedicated to helping customers build outstanding products. Leveraging the latest advancements in the field, and a passion for innovation, we're shaping the future of technology one project at a time. Are you the NEXT one? Role description Are you a battle-tested developer who thrives at the intersection of robust backend logic and seamless frontend experiences? We are looking for an experienced full-stack expert for a fast-paced, short-term assignment to act as a bridge between technology and business. In this role, you will jump straight into an active codebase, advising clients and shaping technical roadmaps while rapidly delivering high-quality mobile features. What You’ll Do: Mobile & Backend Ownership: Build, refine, and optimise mobile features using React Native (Expo) and TypeScript, while ensuring scalable backend services within the Node.js and Firebase ecosystem. Architecture & Integrations: Implement complex mobile UI animations, in-app purchases, and third-party API integrations (such as DeepL and SendGrid). Consulting & Communication: Translate complex technical requirements into business value, collaborate directly with stakeholders, and advise on key technical decisions. Quality & Analytics: Ensure smooth application performance and error tracking using tools like Sentry and PostHog, while establishing shared standards and raising the bar for the entire team. Must Have: Senior-level Expertise: Deep, hands-on production experience with React Native (including the Expo framework) and the modern Node.js ecosystem. Backend Mastery: Solid experience with Firebase services, core Node.js fundamentals, and relational databases (PostgreSQL, MySQL). Targeted Library Mastery: You don't just know React Native; you have deep, practical experience with our exact ecosystem. You are fluent in TanStack Query and Zustand for state/data, react-hook-form, Reanimated for UI, Typesense for search, branch.io for deep linking, and RevenueCat for monetisation. The "Consultant" Mindset: Excellent English communication skills (min. B2/C1+) to efficiently articulate technical decisions to non-technical stakeholders and peers, ensuring minimal management overhead. Nice to have: Practical experience with AI-powered development tools (e.g., Cursor, GitHub Copilot) to enhance coding efficiency. Familiarity with targeted libraries for monetisation (e.g., RevenueCat) and advanced search functionalities (e.g., Typesense). Experience with Cloud & DevOps workflows (AWS, Docker, CI/CD).