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

What we offer 

• Great Place to Work since 2015 - it’s thanks to feedback from our workers that we get this special title and constantly implement new ideas 

• Employment stability - revenue of PLN 2.1BN, no debts, since 2006 on the market 

• We share the profit with Workers - over PLN 76M has already been allocated for this aim since 2022 

• Attractive benefits package - private healthcare, benefits cafeteria platform, car discounts and more 

• Comfortable workplace – class A offices or remote work 

• Dozens of fascinating projects for prestigious brands from all over the world 

• PLN 1 000 000 per year for your ideas - with this amount, we support the passions and voluntary actions of our workers 

• Investment in your growth – meetups, webinars, training platform and technology blog – you choose 

• Fantastic atmosphere created by all Sii Power People 

If you want to work on systems with high operational significance — apply now!