Senior Full-Stack Engineer Java + React 4-6 years of experience

We are a U.S.-based fintech startup operating in the investment and financial services space. Our distributed teams work across Poland, the United States, and Ireland, collaborating on technology-driven solutions related to stocks and investments.

Security, compliance, and the responsible handling of sensitive financial data are central to how we operate, as we build scalable products in a regulated environment.

Responsibilities

- Modernize legacy systems via redesign and refactoring.

- Develop UI using React + Nexus design system.

- Build APIs with proper security and lifecycle governance.

- Design reusable component libraries and UI frameworks.

- Collaborate with UX, product, and architecture teams.

- Optimize frontend and backend performance.

- Support public API documentation and governance.

Skills

- Strong Java + Spring Boot backend capability.

- Expertise in React, TypeScript, Nexus UI components.

- Experience with modernization and migration projects.

- Understanding of microservice and API design.

- Familiarity with CI/CD, linting, testing frameworks.

- Knowledge of frontend security and performance patterns.

- Good collaboration across UX and backend teams.

Important: the candidate must have worked/lived in Poland for the last 2+ years

Please read before applying:

The client is building a product in the bank/investment/brokerage systems niche, and their investors have strict security and compliance requirements, where every person will go through a background check.

What does this mean?

Before making an offer, they will check whether you have violated any EU laws.

For background check — you must be a taxpayer in Poland for 2+ years.