Mjukvaruutvecklare / C#/.NET Software Engineer

Temporary position (vikariat) 24-36 months About KUBAL Kubikenborg Aluminium AB (KUBAL) is Sweden’s only primary aluminum smelter, located in Sundsvall. With approximately 460 employees and over 80 years of operational history, KUBAL is a cornerstone of the Swedish metals industry. Our production runs 24/7, 365 days a year — and the software we build directly supports and controls these mission-critical processes. Our IT team manages everything from infrastructure and OT advisory to custom software development for production systems. You will work on systems that have real, physical impact — from electrolysis cell control to casthouse operations and internal logistics. As a Seveso III upper-tier site, KUBAL is subject to strict safety regulations. We are also actively working to align our cybersecurity practices with NIS2 principles and IEC 62443, making reliability, security, and operational resilience core to everything we do. About the Role We are looking for a skilled C#/.NET Software Engineer to join our IT team on a temporary basis (vikariat, 24–36 months) while a current team member is assigned to a dedicated production system modernization project. This role develops and maintains digital solutions supporting core production processes and auxiliary functions at the smelter. Key Responsibilities Develop and maintain process control software (MES, HMI integrations, dashboards) for casting and electrolysis operations using C#/.NET and Blazor. Build and improve internal web applications running on Kubernetes, including REST APIs, background services, and data pipelines. Integrate with SCADA systems, PLCs, and industrial data sources via OPC UA, MQTT/Sparkplug B, and SQL-based interfaces. Collaborate directly with production engineers, electricians, and operators to translate process needs into working software. Contribute to software architecture, API/interface design, and technical documentation. Ensure operational reliability of mission-critical systems, including participation in on-call rotation and emergency response activities. Use AI-assisted and agentic development tools responsibly to accelerate delivery while keeping code quality, security,, and human review in place. Improve system performance, scalability, and security across the application portfolio. Tech Environment Languages & Frameworks: C#, .NET 10 (LTS), ASP.NET Core, Blazor, Entity Framework Core Databases: MySQL (HA cluster), SQL Server, PostgreSQL Infrastructure: Docker, Kubernetes, Linux (Ubuntu) VMware, on-premises DevOps & Tools: GitLab (CI/CD), Grafana, Keycloak, REST APIs, JSON, XML Industrial / OT: SCADA, OPC UA, MQTT/Sparkplug B, PLC integration, MES AI-Assisted Dev: AI coding agents, MCP integrations, agent guardrails in CI/CD Requirements Bachelor's or Master's degree in Computer Science, Systems Engineering, or equivalent professional experience. At least 2–4 years of proven experience designing and developing scalable, maintainable, and secure software solutions. Strong C#/.NET programming skills (modern .NET; .NET 10 preferred). Experience with relational databases (MySQL, SQL Server, or PostgreSQL), including query writing and basic optimization. Solid understanding of the software development life cycle (SDLC) and version control (Git). Working knowledge of agile practices (Scrum, Kanban) Good communication skills in English (written and spoken). Swedish language skills are strongly preferred for daily collaboration with production teams, operators, and on-site stakeholders. Merits (Preferred Skills & Experience) Web & Frontend: Experience with modern web UI frameworks (Blazor, React, Angular, or Vue) and frontend tech (HTML, CSS, JavaScript/TypeScript); familiarity with mobile development. Infrastructure & DevOps: Hands-on experience with Docker containers and Kubernetes orchestration. Experience with CI/CD pipelines (GitLab CI, GitHub Actions, or similar) Experience with high-availability (HA) MySQL clustering or database replication; Familiarity with Linux server administration (Ubuntu). Quality & Testing: Hands-on expertise in Test-Driven Development (TDD) and unit testing frameworks (xUnit, NUnit, MSTest); Experience with integration testing and code quality tools. (SonarQube, linting) Identity & Integration: Experience with identity management Active Directory, Keycloak, OAuth 2.0/OpenID Connect (OIDC), or similar on-premises IAM solutions); Experience with document automation (Microsoft Office APIs, OpenXML, or reporting frameworks); Working experience with Grafana or similar data visualization and monitoring tools. Industrial & Domain: Familiarity with industrial protocols and systems (OPC UA, MQTT, SCADA, HMI, PLC); interest in or experience with heavy industry, process manufacturing, or production environments; Experience with C++ for embedded or performance-critical systems. AI-Assisted & Agentic Development: Daily use of AI coding agents (Claude Code, OpenAI Codex, GitHub Copilot agent mode Cursor, or similar) including planning, reviewing, and taking full ownership of AI-generated code. What We Offer Competitive salary, set individually based on experience and qualifications. Occupational pension (ITP) and insurance benefits. A small, high-impact team where your work directly supports real production operations. Broad technical exposure: from web applications and cloud-native infrastructure to industrial OT systems. Professional development opportunities and conference attendance. Sundsvall offers excellent quality of life: affordable housing, short commutes, world-class outdoor recreation, and proximity to both coast and mountains. Employment Terms Type: Temporary (vikariat), 24–36 months, substituting for a team member assigned to a dedicated production system modernization project Start date: As per agreement Probation: 6 months Location: Sundsvall (on-site) Salary: Competitive, set individually based on experience and qualifications Reporting: The C#/.NET Software Engineer reports directly to the Head of IT. Contact Information For questions about the position, contact: Yevgen Izvyekov, IT chef – 073-988 80 42 Trade union representatives: Unionen: Patrik Bergström, 073-986 0739 Ledarna: Marcus Lansink, 073-988 58 88 Application Process Please send your application marked "Mjukvaruutvecklare / C#/.NET Software Engineer" to jobb@kubal.se as soon as possible, but no later than December 31, 2026. Applications are processed on an ongoing basis, so the position may be filled before the deadline.