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

• 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
  
  

Job no. 260515-2HZ84

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.

Benefits For You

Great Place to Work

Solid financial situation

Contracts with the biggest brands

Centre of internal trainings

Many experts you can learn from

Open and accessible management team

Profit sharing

Passion Sponsorship program

Regular integration events and trips

Comfortable and well-equipped offices

MySii app

Medical care