Fullstack .NET Developer
Client:
Agency of the United Nations Location:
Vienna, Austria (On-site - no remote work allowed) Type of Engagement:
Freelance / T&M consultancy - initial 6 months, renewable (long-term engagement) Rate:
Max 400 euro per day all inclusive Start:
ASAP Relocation:
no relocation support or visa sponsorship provided For an Agency of the United Nations, we are looking for a Fullstack .NET Developer to design, develop and maintain secure integration components and plugins within an enterprise system environment. The role focuses on enterprise-grade .NET (C#) development, system interoperability and secure data exchange with external governmental and financial intelligence systems. Main Responsibilities:
Analyze business and technical requirements provided by stakeholders and system architects Review external system interfaces (APIs, databases, XML feeds) to determine the integration approach Design integration solutions using .NET (C#) aligned with the system architecture Define the data flow between the platform and external systems, object models (POCOs) and mapping strategies, and the authentication and security approach (tokens, certificates, etc.) Hard Skills:
Minimum 5 years of professional experience in software development, including at least 3 years of hands-on C# (.NET) development Minimum 2-3 years of hands-on DevOps experience in enterprise environments Experience in secure software development for sensitive data environments Object-oriented design and POCO modelling: DTO domain model separation, layered architecture, SOLID principles and clean code; POCO-to-POCO mapping, both manual and with frameworks such as AutoMapper; schema-driven models HTTP-based network programming in .NET: HttpClient, HttpRequestMessage / HttpResponseMessage lifecycle, synchronous and asynchronous programming (async/await) Integration with RESTful APIs and SOAP services, including retry policies, timeout handling, connection resilience and proxy configuration in secure government environments Secure authentication in .NET: OAuth 2.0, JWT handling and validation, API key authentication, token lifecycle management, secure storage of secrets, bearer tokens on outbound requests Secure communication: TLS/HTTPS enforcement, certificate validation and handling JSON and XML serialization/deserialization, mapping between external payloads and internal POCO models, validation of structured data before transmission Familiarity with logging, auditing and traceability in integration systems (preferred) University degree (Bachelor's or equivalent) in computer science, information systems or a related field Soft skills:
Fluency in English is required; knowledge of another UN official language is desirable Ability to analyze requirements and work closely with stakeholders and system architects The ideal candidate is an experienced C# / .NET developer with a strong background in secure system integrations, available to work onsite in Vienna. What do we expect from you?
We expect enthusiasm and creative solutions. Active contribution to nurture the Community with research, scouting and concept of new solutions will be required. OUR Client
Agency of the United Nations based in Vienna. www.dropacode.com
