Senior .NET Backend Engineer – Scalable E‑commerce

Sigma Software; Warszawa; On-site; PLN 180,000 - 260,000; Full time

Job summary

Sigma Software in Warszawa is hiring a Senior/Middle .NET Developer for a large-scale E-commerce Marketplace. You will work on back-end development, integration, and scalability within an international team, contributing to a high-load ecosystem.

You will design and implement robust features, participate in the full development lifecycle, and help ensure performance, reliability, and security across services and databases.

Qualifications

• 4+ years of commercial software development with .NET/C#.
• Familiarity with .NET Framework 4.8 and OO design.
• Experience with MSMQ and WCF or similar techs.
• Strong SQL Server knowledge and T-SQL skills.
• Experience with distributed caching (NCache or similar).
• Understanding of distributed systems and event-driven architecture.
• Experience with unit, integration, and performance testing.
• English level at least Upper-Intermediate.

Responsibilities

• Design, develop, and maintain robust backend solutions in .NET.
• Own features from analysis to production deployment.
• Build scalable, secure, and well-tested code.
• Support and optimize distributed messaging and services.
• Collaborate with cross-functional teams across borders.
• Contribute to monitoring, troubleshooting, and performance tuning.

Skills

.NET/C#

MSMQ/WCF

SQL Server

Distributed caching

Distributed systems

Unit/integration testing

English (upper-intermediate)

Tools

NCache

Job description

Sigma Software in Warszawa is hiring a Senior/Middle .NET Developer for a large-scale E-commerce Marketplace. You will work on back-end development, integration, and scalability within an international team, contributing to a high-load ecosystem.

You will design and implement robust features, participate in the full development lifecycle, and help ensure performance, reliability, and security across services and databases.