Senior .NET Developer (Energy / Mission-Critical Systems)

About us We are a Zagreb-based young team of hard-working and enthusiastic experts located right in the city center in beautiful new offices, dedicated to providing custom software development and other product lifecycle services, on both internal and external projects. We are a leader in energy transition, using optimization and machine learning to facilitate a green economy. We are big supporters of proactiveness and are always open to supporting innovative ideas. We are hiring a Senior .NET Developer for long-term, mission-critical systems in the energy sector — systems with hard availability targets, real integrations, and users who depend on them daily. If you're interested in end-to-end development and want to work with cutting-edge technologies, come on board. 🚀 Your responsibilities Backend development in C# / .NET Core — web APIs, background workers and Windows services, data ingestion and transformation pipelines,Frontend development in React + TypeScript — data-heavy screens: dashboards, KPI alerts, time series in fine granularity, large filterable and exportable grids, charting,Design and build integrations: REST and SOAP web services, JSON and XML payloads and schemas, file-based exchange, message-driven flows, third-party APIs and SDKs,Model and query relational data at scale — MS SQL Server / PostgreSQL, time-series and scenario data, query and index tuning against tight response-time targets (sub-500 ms user interactions),Write and maintain automated test suites — unit, integration, end-to-end and performance tests; take part in regression and destructive testing before releases,Build and maintain CI/CD pipelines, containers and deployment automation across multiple environments (dev, test, UAT, pre-prod, production, DR),Build for high availability, auditability and security by default: RBAC, SSO/MFA, immutable audit logs, encryption, backup/restore and DR procedures,Diagnose production incidents, do root cause analysis, and write the runbooks and technical documentation that go with the system,Plan tasks and activities with the Project Manager and teammates, and collaborate with the Project Lead, other developers and the client's technical staff — directly, in English,Have regular professional development programs.Requirements 5+ years of professional software development experience, with a meaningful part of it in a senior or lead capacity,Masters in Computer Science, Mathematics, Statistics, Electrical Engineering or another related fieldAdvanced knowledge of C# and .NET (preferably .NET Core / .NET 8+) — ASP.NET Core Web API, Entity Framework Core or Dapper, async programming, multithreading, background/Windows services,Advanced knowledge of JavaScript and/or TypeScript, preferably ReactJS, plus solid HTML and CSS,Advanced knowledge of REST and SOAP web services, and comfort working with XML/XSD as a first-class integration format (not just JSON),Good knowledge of data structure design and SQL database management systems — MS SQL Server and/or PostgreSQL, including performance tuning,Experience with version control and CI/CD in Git / GitLab (or equivalent),Experience writing and maintaining automated tests, and working in an Agile/Scrum team with code review,Excellent command of English — English is the working language, with day-to-day contact with international client teams. Croatian is an advantage but not a requirement,Team player, proactive, thoughtful and efficient problem solver; able to perform independently or in a small team,A pragmatic approach, biased to simplicity, where you most care about achieving impact.Considered a strong plus Experience in the energy sector — TSO/DSO systems, SCADA/EMS, electricity markets (day-ahead, intraday, balancing), energy trading, or grid and market data models,Familiarity with energy domain concepts and standards: system adequacy (LOLE/LOLP/EENS), outage management, ENTSO-E Transparency Platform / REMIT, ECP/EDX, CIM, or simulation tools such as PSS/E, PowerFactory, PyPSA,Docker and orchestration systems (Kubernetes), infrastructure as code, Azure,Observability and monitoring in production: structured logging, metrics, Grafana / Application Insights / equivalent,Windows Server, IIS, Active Directory and on-premise deployment experience,Identity and access: Microsoft Entra ID (Azure AD) SSO, MFA, OAuth2/OIDC, SAML 2.0, granular RBACSecure development practices — OWASP Top 10, SAST/DAST in the pipeline, vulnerability remediation; awareness of NIS2 and GDPR requirements,Python for services, tooling and data work,Reporting and BI integration (Power BI), and data visualisation for large time-series datasets,Mathematical optimization or simulation (Gurobi, HiGHS, linear programming) — we use optimization across our energy projects,ITIL-style incident, problem, change and release management; experience with ServiceNow or a comparable ITSM tool,Passion to experiment with new technologies from the frontend, backend and ML ecosystem.Practical requirements Comfortable joining regular calls with the client's technical teams, in English,Work is performed from the EU (our Zagreb office / hybrid) — our clients require EU data residency, so this is not a fully remote non-EU role,Occasional travel to client locations in the EU for workshops and reviews.Why choose Uprise? Professional development – Challenging tasks, opportunity to work on different projects and to express and implement your ideas. You'll work on long-term systems that stay in production for years, for demanding international clients.Culture - Team spirit, passion, creativity, flexibility and proactiveness are the drivers of our company.Salary & Perks – Competitive salary, flexible working hours, team buildings, after work beers and sports.