Senior .NET Backend Engineer, High-Load E-commerce

Sigma Software; Województwo mazowieckie; On-site; PLN 180,000 - 240,000; Full time

Job summary

Sigma Software is seeking a Middle/Senior .NET Developer to help evolve a large-scale e-commerce ecosystem. You will work on integrating a new platform into the main system, focusing on scalability, reliability, and performance across distributed services.

Join a cross-functional team of engineers and QA, contributing to full SDLC and enterprise-grade backend solutions. Strong experience with MSMQ, WCF, and SQL Server is required.

Qualifications

• 4+ years of commercial .NET/C# development experience.
• Familiarity with .NET Framework 4.8.
• Strong knowledge of distributed systems and software architecture principles.

Responsibilities

• Design, develop, and maintain backend solutions using .NET Framework 4.8 and C#.
• Take ownership of features throughout the full development lifecycle, from requirements analysis to production deployment.
• Develop clean, maintainable, scalable, and well-tested code following engineering best practices.
• Support, optimize, and troubleshoot distributed messaging and service-oriented systems built with MSMQ and WCF.
• Design and optimize SQL Server database structures, queries, indexes, and stored procedures.
• Implement and maintain distributed caching solutions using NCache or similar technologies.
• Participate in architectural discussions focused on scalability, reliability, and system performance.
• Collaborate closely with developers, QA engineers, DevOps specialists, and product stakeholders.
• Contribute to system monitoring, troubleshooting, and production issue resolution.
• Ensure high standards of application performance, security, and maintainability.

Skills

Distributed systems

Event-driven architecture

C# / .NET

MSMQ

WCF

SQL Server

Software architecture

Unit/integration testing

English (Upper-Intermediate)

Tools

MSMQ

WCF

NCache

SQL Server

Visual Studio

Job description

Sigma Software is seeking a Middle/Senior .NET Developer to help evolve a large-scale e-commerce ecosystem. You will work on integrating a new platform into the main system, focusing on scalability, reliability, and performance across distributed services.

Join a cross-functional team of engineers and QA, contributing to full SDLC and enterprise-grade backend solutions. Strong experience with MSMQ, WCF, and SQL Server is required.