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April 8, 2026

Fullstack Developer (.NET + React)

Senior • Hybrid

120 - 140 USD

Warsaw, Poland

We’re looking for an experienced Full-Stack Developer to build and evolve business applications using C#/.NET on the backend and React on the frontend. You’ll work closely with a cross-functional team (QA, Analysts, Product Owner) in an Agile/Scrum environment, contributing to both new development and improvements to existing (including legacy) codebases.

Key responsibilities:

  • Develop software in C# based on functional and technical documentation

  • Build and maintain the frontend using React (18+)

  • Analyse and improve existing code, including legacy components

  • Contribute to solution design and architecture

  • Collaborate daily with developers, testers, analysts and the Product Owner in Scrum

Requirements:

  • 5+ years of experience building applications with .NET / C#

  • 3+ years of experience building applications with React

  • Strong knowledge of C# (.NET Framework, .NET Standard, .NET Core/.NET)

  • React experience with modern versions (React 18+)

  • Practical skills in debugging, profiling and performance analysis

  • Understanding of DDD, Clean Code, SOLID

  • Knowledge of architectural patterns and asynchronous communication

  • Good command of T-SQL and SQL Server Management Studio (SSMS)

  • Experience working with Visual Studio

Nice to have

  • Experience building views/UI for mobile applications

  • Background in projects for the financial sector

  • Test automation experience (e.g., Postman, Playwright)

  • Familiarity with WCAG accessibility standards