React Developer (f/m/x)
Join a team building a modern fintech platform that helps businesses manage company spending more efficiently. The project focuses on developing a financial product that enables seamless integration of financial tools—including corporate cards, expense management, and invoice processing—directly with partner ecosystems such as banks, accounting platforms, and HR systems. The platform empowers companies to automate financial operations, simplify reconciliation processes, and gain full real-time visibility into their spending.
Your tasks
Lead initiatives focused on designing, building, and maintaining scalable front-end applications primarily using React and TypeScript
Build modern, performant, and intuitive user interfaces for key areas of the fintech platform
Collaborate closely with cross-functional teams across backend engineering, product, and design to deliver scalable product solutions
Integrate front-end applications with microservices-based architectures and APIs (REST / GraphQL)
Analyze application performance and implement optimizations to ensure high responsiveness, reliability, and scalability
Participate in code reviews, architecture discussions, and post-mortems while mentoring other engineers
Proactively address technical debt and guide the team through technical challenges, refactoring initiatives, and architectural migrations
Requirements
At least 5 years of professional software engineering experience, including strong commercial experience with React
Strong expertise in TypeScript, modern JavaScript (ES6+), and building large-scale SPA applications
Solid experience designing scalable front-end architectures using component-based and modular design principles
Experience working with APIs and distributed systems in microservices-based environments
Hands-on experience with front-end testing frameworks (unit, integration, e2e) and observability/monitoring tools
Previous work with CI/CD pipelines, cloud environments such as AWS, and container orchestration platforms like Kubernetes
Strong problem-solving skills, ownership mindset, and passion for mentoring and elevating engineering teams
Professional English proficiency - minimum B2
Fluent in Polish required
Residing in Poland required
Nice-to-have requirements
Previous experience in fintech or building financial products
Understanding of payments, cards, expense management, or accounting-related domains
Experience working in a scale-up environment
Experience with GraphQL, SSR, performance optimization, or building design systems

Sii
Sii Polska to czołowy dostawca doradztwa technologicznego, transformacji cyfrowej oraz usług biznesowych i inżynieryjnych. Firma obecna jest na rynku od 2006 roku, zatrudnia ponad 7 500 ekspertów, jedenastokrotnie zdobył...React Developer (f/m/x)
React Developer (f/m/x)