Senior Fullstack Developer .NET + React

We are looking for a Senior Fullstack Developer to join a new banking project focused on developing a microfactoring platform. The role combines backend development in C#/.NET with frontend development in React, working across microservices and existing applications while contributing to solution architecture, performance optimisation, and high-quality software delivery within a Scrum team.
Responsibilities
• Develop software in C#/.NET
• Develop frontend functionality in React
• Analyse and develop existing code
• Work with legacy applications where required
• Participate in solution architecture
• Design and develop new functionality
• Debug and profile applications
• Analyse application performance
• Work with relational databases and TSQL
• Work with asynchronous communication patterns
• Cooperate closely with Developers, Testers, Analysts and Product Owner
• Participate in Scrum delivery
• Maintain code quality and development standards

Requirements

• Minimum 5 years commercial .NET development experience
• Minimum 3 years commercial React development experience
• Strong C#
• .NET Framework
• .NET Standard
• .NET Core / modern .NET
• React 18+
• Debugging and profiling
• Performance analysis
• DDD
• Clean Code
• SOLID
• Architectural patterns
• Asynchronous communication
• TSQL
• SQL Management Studio
• Visual Studio
• Fluent Polish
• English minimum B2
Nice to have
• Experience developing mobile application views
• Banking or financial services experience
• Automated testing
• Postman
• Playwright
• WCAG

Benefits

• Flexible hybrid model (1 day/week onsite in Warsaw/Gdańsk)
• Solid, competitive salary
• Work in a multinational environment on international projects
• Comprehensive healthcare
• Long-term B2B contract with a stable project pipeline