Senior Software Engineer (C# / .NET) - Contractual Role

About us: Working at Tech Holding isn't just a job, it's an opportunity to be a part of something bigger. We are a full-service consulting firm that was founded on the premise of delivering predictable outcomes and high-quality solutions to our clients. Our founders and team members have industry experience and have held senior positions in a wide variety of companies – from emerging startups to large Fortune 50 firms – and we have taken our combined experiences and developed a unique approach that is supported by the principles of deep expertise, integrity, transparency, and dependability. About the Role We are looking for a skilled Senior C# / .NET Engineer to support a critical platform security and modernization initiative. This role focuses on backend/API enhancements, security implementation, and system reliability improvements in alignment with Azure- based infrastructure and data protection standards. Key Responsibilities  Design and develop secure backend services and APIs using C# / .NET.  Implement authentication and authorization mechanisms (SSO, RBAC, OAuth, JWT).  Integrate applications with Azure Active Directory (Entra ID).  Remove hardcoded secrets and integrate with Azure Key Vault.  Implement audit logging and monitoring hooks across services.  Build and enforce secure API communication standards.  Implement PII masking and secure data handling logic in applications.  Secure and optimize third-party integrations (Stripe, SendGrid, Twilio, etc.).  Support environment separation and deployment improvements.  Collaborate with DevOps and DB teams on security, DR, and compliance initiatives.  Participate in debugging, incident resolution, and root cause analysis. Requirements:  5+ years of experience in C# / .NET development.  Strong experience with ASP.NET Core, Web APIs, and microservices architecture.  Experience implementing authentication & authorization (OAuth, JWT, SSO).  Hands-on experience with Azure services, especially Azure AD (Entra ID).  Experience with secure coding practices and data protection.  Familiarity with API integrations (Stripe, SendGrid, etc.).  Experience with logging frameworks and monitoring tools.  Understanding of CI/CD pipelines and cloud deployments.  Strong debugging, problem-solving, and communication skills. Good to Have  Experience with containerization (Docker, Kubernetes) Tech Holding is proud to be an Equal Opportunity Employer and is committed to fostering a diverse and inclusive workplace. We welcome applicants from all backgrounds and experiences, and we consider qualified applicants without regard to race, color, religion, gender, sexual orientation, gender identity, national origin, disability, veteran status, or any other legally protected characteristic. If you require accommodation in the application process, please contact our HR