Senior FullStack .NET Developer (React, FinTech)

TL;DR

Senior FullStack .NET Developer (React, FinTech): Building and optimizing high-scale backend services and interactive user interfaces for a US-based FinTech leader with an accent on architectural excellence, robust API design, and a product-first mindset. Focus on solving complex distributed systems puzzles, driving frontend development, and ensuring world-class User Experience.

Location: Hybrid in Warsaw, Poland, with a flexible remote policy within Poland. Global collaboration with US-based Product Managers and Stakeholders.

Salary: 18.000–25.000 PLN B2B

Company

The client is a fast-growing US-based leader in the Financial Technology sector with a major engineering hub in Warsaw.

What you will do

• Own features end-to-end, from database schema and API design to the final React component.
• Contribute to the evolution of a Cloud-Native microservices architecture on Azure.
• Maintain high engineering standards (SOLID, Clean Code, Design Patterns) while ensuring velocity.
• Drive the development of responsive, high-performance web applications using React.
• Partner closely with US-based Product Managers and Stakeholders.
• Lead by example through Code Reviews and knowledge sharing to elevate the Warsaw engineering hub.

Requirements

• 5+ years of experience in .NET (.NET 6/8+) and C#, with expertise in building RESTful APIs and event-driven architectures.
• Solid experience with React and TypeScript, including state management (Redux, Zustand, or React Query).
• Practical experience with Azure (App Services, Functions, Service Bus, Cosmos DB/SQL).
• Strong skills in SQL Server and Entity Framework Core.
• Hands-on experience with Docker, Kubernetes, and CI/CD pipelines (Azure DevOps/GitHub Actions).
• English: C1 required for daily collaboration with the US team.

Nice to have

• Experience in high-growth FinTech, WealthTech, or high-frequency trading environments.
• Knowledge of testing frameworks (xUnit, Jest/Cypress).
• Familiarity with Web Performance optimization and Accessibility (WCAG).

Culture & Benefits

• Transparent, high-growth US tech culture valuing radical candor, innovation, and initiative.
• Access to the latest tech on the bleeding edge of .NET and React.
• Vibrant, well-located modern Warsaw office for collaboration.
• Competitive compensation package.
• Opportunity to power mission-critical systems used by financial professionals globally.