Project B2B: Senior .NET Developer (Cybersecurity)

B2B Project: Senior .NET Engineer (Cybersecurity)

Hays IT Contracting is a cooperation based on B2B rules. We connect IT specialists with the most interesting technological projects on the market. For our client, an international organisation modernizing business-critical applications based on legacy .NET technologies, we are currently looking for an experienced specialist for the position of Senior .NET Engineer (Cybersecurity).

• Service delivery model: Fully remote
• Rate: 150–195 PLN/h net (+ VAT), negotiable depending on experience and expertise
• Start Date: ASAP
• Cooperation: Long-term, multi-year project
• Cooperation type: B2B, through Hays Poland
• Language: English C1; German nice to have

Project Description The project focuses on the modernization of business-critical applications currently running on legacy .NET Framework versions 4.5.x–4.8. The existing solutions are predominantly monolithic and hosted on traditional virtual servers. The modernization initiative aims to address architectural limitations, introduce modern orchestration, and align the applications with current cybersecurity and SSDLC standards. The scope includes migrating applications to an on-premise Service Fabric cluster, using Reliable Services or containers, as well as implementing security controls, automated deployment processes, and modern identity and configuration management mechanisms.

Technology environment

• .NET Framework 4.5.x–4.8
• Service Fabric
• Reliable Services
• Containers
• Stateless / Stateful services
• SSDLC
• SAST / DAST
• OIDC / OAuth2
• CI/CD
• Infrastructure as Code (IaC)
• Security scanning
• Data encryption
• Frontend technologies, where applicable

Scope of services

• Modernize existing monolithic applications based on legacy .NET Framework versions.
• Port and adapt application code for deployment as Reliable Services or Containers within an on-premise Service Fabric cluster.
• Optimize service communication, state management for stateless and stateful services, and health monitoring integration.
• Integrate cybersecurity requirements and security gates into the development and delivery process.
• Support alignment of the solutions with SSDLC requirements, including SAST/DAST reporting.
• Implement secure configuration management and identity mechanisms using OIDC/OAuth2.
• Apply appropriate data encryption standards within the modernized solutions.
• Implement automated CI/CD pipelines using Infrastructure as Code principles.
• Incorporate automated testing and security scanning into deployment pipelines.
• Support zero-downtime deployment approaches, including rolling upgrades to the Service Fabric cluster.
• Prepare detailed technical documentation of the modernized architecture.
• Conduct knowledge-transfer sessions for the internal DevOps and security teams.
• Cooperate within an international project environment, primarily involving stakeholders based in Germany.

Required competencies

• Minimum 5 years of commercial experience with .NET Framework, particularly versions 4.5.x–4.8.
• Practical cybersecurity experience, including SSDLC Compliance, SAST/DAST, and OIDC/OAuth2.
• Experience with Service Fabric; alternatively, relevant experience with Reliable Services or Containers may be considered.
• Experience in modernizing monolithic applications and/or application integrations.
• Ability to deliver services in English at C1 level.

Nice to Have

• Experience with frontend technologies.
• German language skills.

Cooperation process

• Profile and experience review by the Hays team
• A conversation with a Hays consultant about the project and scope of services
• Technical meeting(s) with project representatives, up to 2 stages
• Agreement on cooperation terms
• Welcome to the project!

The cooperation is carried out between independent businesses (B2B model) and covers the performance of services within the agreed project scope. The Contractor independently organizes and manages the manner in which the services are performed, taking into account the project requirements, security obligations, and the necessary communication with the client. Any information regarding location, availability, or project meetings is provided solely for organizational purposes and shall not be construed as creating an employment relationship, employer-like supervision, or performance of work under the direction or control of the client.

#1200085 - Malgorzata Pawelczyk