Sigma Software
OpenMiddle/Senior .NET Developer (Construction)
- Location
- Krakow or Warsaw, or whatever, pl
- Posted
- Aug 11, 2026
- Last seen
- Aug 20, 2026
About the role
Design, develop, and maintain robust Back-end solutions using C# and .NET Participate in architecture discussions and contribute to technical solution design Develop and integrate RESTful APIs and SOAP web services Work on core modules development and perform refactoring when necessary Collaborate closely with developers, QA engineers, DevOps specialists, architects, and Product Owners Clarify business and technical requirements with internal and Customer-side teams Write and maintain unit, API, and integration tests Participate in peer code reviews and follow engineering best practices Investigate and introduce new technologies and technical improvements Troubleshoot issues across application, infrastructure, and database layers Prepare and maintain technical documentation Contribute to Front-end-related tasks using Angular and TypeScript when needed 4+ years of commercial software development experience with C# and .NET Strong experience designing, developing, and integrating Web APIs, including RESTful APIs and SOAP services Solid understanding of OOP, SOLID principles, and common design patterns Strong knowledge of Microsoft SQL Server and T-SQL Practical experience with LINQ, ADO.NET, and Entity Framework Experience working with event-driven systems and message brokers Experience writing and maintaining unit, API, and integration tests Experience with Angular or another modern Front-end framework/library Good knowledge of TypeScript Understanding of Front-end architecture, maintainability, and performance optimization Strong troubleshooting and debugging skills across application, database, and infrastructure layers Confident Git usage, including branching strategies, pull requests, and code reviews Intermediate or higher English level Strong communication skills and ability to work collaboratively in a cross-functional environment WILL BE A PLUS: Experience with NoSQL databases Experience using AI-assisted development tools such as GitHub Copilot or Claude
