Join a product-focused engineering team developing solutions for the European construction industry. We are looking for a Middle/Senior .NET Developer who is ready to contribute not only to implementation but also to architecture discussions, technical improvements, and product evolution.

At Sigma

Software, you will become part of a mature delivery team with predominantly Senior-level specialists, collaborating closely with architects, QA engineers, DevOps experts, and Product Owners. CUSTOMER Our Customer is a European technology company specializing in solutions for construction site security, access management, and operational transparency. Over the past 15+ years, the company has evolved from a smart-lock product into a large ecosystem of web, mobile, and server-side solutions supporting construction businesses across Europe.

The engineering organization includes distributed international teams and long-term collaboration with Sigma Software specialists. PROJECT The project is part of a large-scale product ecosystem designed for the European construction market. The platform helps construction companies manage access control, subcontractor relationships, security compliance, and operational risks across construction sites.

In this role, you will contribute to a system focused on analyzing companies involved in the construction process. The product enables site operators to monitor subcontractors, maintain compliance standards, and reduce long-term reputational and operational risks.

Project technologies: C#, .NET, REST APIs, SOAP, MS SQL Server, Entity Framework, Kafka, Angular, TypeScript, Azure 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 Qualifications 4+ years of commercial software development experience with C# and .NET

Solid 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

📌 Middle/Senior .NET Developer (Construction) (Banana Shire)
🏢 Sigma Software
📍 Banana Shire