Senior React Native Developer

About the Position

Join one of Europe's largest mobile platforms, delivering digital services used by millions of users across multiple countries in Europe and North America. Built on a multi-module architecture, the platform enables rapid product development, high code reusability, and continuous expansion into new business areas.

As a Senior React Native Developer, you will play a key role in shaping the architecture of a big mobile ecosystem, driving technical decisions, mentoring other engineers, and delivering high-quality solutions at scale.

Responsibilities

• Design, develop, and maintain complex mobile applications using React Native and TypeScript
• Drive architectural decisions and contribute to the evolution of our multi-module platform
• Lead technical discussions and participate in solution design
• Review code, mentor team members, and promote engineering best practices
• Collaborate closely with Product Owners, UX Designers, Backend Engineers, QA Engineers, and Architects
• Improve application performance, reliability, scalability, and maintainability
• Contribute to CI/CD processes and development tooling
• Support the integration of native mobile capabilities and third-party services
• Identify technical debt and proactively drive improvements across the codebase

Requirements

• At least 5 years of commercial software development experience, including at least 4 years with React Native
• Proven track record of building and maintaining large-scale mobile applications
• Strong expertise in TypeScript, modern JavaScript, and React Hooks
• Solid understanding of modular and multi-module application architecture
• Hands-on experience with MobX and React Query (TanStack Query)
• Knowledge of native mobile development concepts and creating native modules for iOS and Android
• Practical experience with REST APIs, GraphQL, and form management solutions
• English and Polish proficiency at B2 level or higher
• Residing in Poland required

Nice to Have

• Payment integrations and mobile wallet solutions
• Geolocation and location-based services
• Firebase services and analytics
• Mobile security best practices
• Observability and monitoring tools
• Background in large-scale international products
• Agile delivery experience (Scrum/Kanban)

Technologies & tools

Must have

• React Native
• TypeScript
• MobX
• React Hooks
• React Query/ TanStack Query
• React Native Reanimated
• Axios REST APIs
• Apollo Client GraphQL
• GitHub Actions
• Shopify FlashList

We Offer

• Great Place to Work
• Стійкий фінансовий стан
• Контракти з найбільшими світовими брендами
• Центр внутрішніх навчань
• Багато експертів, у яких можна повчитися
• Відкрита та доступна команда менеджменту
• Profit sharing
• Passion Sponsorship Program
• Регулярні інтеграційні заходи та подорожі
• Комфортні та добре обладнані офіси
• MySii app
• Медичне страхування

About the Company

Sii ensures that all hiring decisions are made solely on the basis of qualifications and competence. We are committed to equal and fair treatment of all, regardless of legally protected characteristics. At Sii, we promote a diverse and inclusive work environment, in full compliance with applicable anti-discrimination laws.

Job no. JOB-NHA43