Senior .NET backend developer | MS SQL, REST API, AI - Tietoevry Tech Services (m/f/d)

Who we are:

We are small internal development team. We are part of a large international Tietoevry Tech Services Security Team located in Finland, Norway, Sweden and Czechia. We are looking for Senior .NET Software Developer who will work with us on our internal SOAR platform which we are running for more than ten years.

The whole platform is written in C# with TDD approach and is based on a set of Windows services, WPF desktop application, REST API, .NET Core, MS SQL Cluster, Elasticsearch stack, Apache NiFi, Apache Kafka, and Power BI. We have integrated many on-premises and cloud platforms for the Security Operations Center and other divisions of Managed Security Services. The platform provides centralized monitoring, data transfers, automation, reporting, response support, remote system control, user-defined workflows, and interactive playbooks for hundreds of thousands of devices and users.

In our team, we are heavily focused on code quality, people's ideas, and professional growth. If you have an idea or want to experiment with some promising technology, you have free hands. We have reserved a regular day per sprint for the learning to keep our people on a good technical level. Besides traditional code review for every pull request and automated builds, we have also regular tasks for continuous code quality improvement to avoid some legacy code or security risks.

With us as a Senior .NET Backend Developer:

you will be a key contributor to the development of our SOAR platform. Your responsibilities will include:

• Designing and building the backend layer, including:

  • Developing the DataLayer on top of Microsoft SQL Server, with a focus on schema design and query optimization

  • Implementing and consuming REST APIs for integration with security providers (Azure, AWS, Google Cloud) and 3rd-party security tools

  • Extending our custom workflow engine, enrichment APIs, and backend logic

  • Participating in the development of the web portal and reporting infrastructure

• Working on AI-driven features to enhance the efficiency of Security Operations, such as:

  • Alert classification, summarization, and triage using models like OpenAI / Azure OpenAI

  • Automating playbook actions and recognizing patterns that trigger automated responses

We expect you to have:

• Strong experience with C#

• Proficiency in T-SQL, Entity Framework, and Dapper, including hands-on work with database schema design and query optimization

• Solid understanding of REST APIs:

  • Creating and consuming endpoints

  • Familiarity with Swagger/OpenAPI, OAuth2, JWT, OpenID, and Role-Based Access Control (RBAC)

• Experience with Test-Driven Development (TDD) and mocking frameworks

• Proficient in:

  • Asynchronous programming, parallelism

  • Efficient memory usage (Span, Memory)

  • Writing high-performance backend code

• Knowledge of Dependency Injection, CQRS, Mediator pattern, and event-driven architectures

• Hands-on experience integrating with OpenAI, Azure OpenAI, or similar APIs (e.g., ChatGPT, GPT-4)

Bonus Points / Nice to Have:

• Experience with SignalR, Apache Kafka, or Azure Service Bus

• Exposure to prompt engineering and building intelligent UI/UX powered by LLMs

• Integration of ML workflows using ML.NET or other .NET-compatible ML tools

• Knowledge of Elasticsearch / Kibana development

• Experience with ASP.NET Core, Blazor, TypeScript, or modern web technologies

• Working in Agile (SCRUM) environments with Git (Azure DevOps), JIRA

• Awareness of security best practices in backend development

We offer:

• Contract is for an indefinite period of time > we count on you!

• work partially or completely remote > work from wherever it suits you
• extra holidays > we have 25 days off plus 2 sick days.
• we contribute from 10 400 CZK per year > you name it. Choose from contributions for pension and life insurance, sports, culture, health, travel or education in the cafeteria.
• educate yourself > we regularly organize and pay for IT courses, certifications, language training and personal development courses
• 107 CZK meal allowance on top of your salary
• reward for a new colleague > refer another colleague to us and get up to 80,000 CZK
• we'll support you when you're sick > for colleagues who are seriously ill for a long period of time, we contribute to sick pay in excess of the law
• extra work is appreciated > when overtime is needed, we pay more than the law requires
• stay fit and fresh > in Ostrava, use the free fitness facilities in the building, in other locations, do sports with Multisport
• Nordic culture > we believe in you. No one is breathing down your neck and checking every minute of your work. We are friendly and open.

#LI-Hybrid

#LI-TM1