Senior C#/.NET Engineer – Enterprise Applications | Long-Term

We are looking for a highly experienced Senior C#/.NET Engineer for a long-term engagement supporting and developing enterprise-level software applications. The ideal candidate has 8+ years of hands-on professional experience with C# and .NET, strong experience building enterprise applications and RESTful APIs, and the ability to independently take ownership of complex development tasks from requirements through implementation, testing, troubleshooting, and delivery. This position is best suited for an experienced engineer who is technically strong, communicates clearly in English, works well in a remote team environment, and is interested in a long-term collaboration with consistent weekly availability. 1. Responsibilities - Design, develop, test, deploy, maintain, and enhance scalable enterprise applications using C# and .NET technologies. - Develop and maintain ASP.NET Core applications, Web APIs, RESTful services, and backend components. - Write clean, maintainable, secure, testable, and high-performance production code. - Take ownership of assigned features and technical tasks from requirements analysis through implementation, testing, and delivery. - Analyze existing applications and codebases, identify technical issues, and implement practical improvements. - Troubleshoot complex application issues, perform root-cause analysis, and resolve production and development problems. - Participate in architecture discussions, technical design decisions, and implementation planning. - Apply Object-Oriented Programming, SOLID principles, design patterns, and software engineering best practices. - Participate in code reviews and contribute to maintaining high development and code-quality standards. - Collaborate effectively with developers, product managers, technical leads, and other stakeholders. - Participate in Agile/Scrum development processes, including planning, refinement, stand-ups, reviews, and retrospectives. - Contribute to long-term product development, modernization, scalability, performance, and continuous improvement. 2. Required Qualifications - 8+ years of professional software development experience with C# and .NET. - Strong hands-on experience with C#, .NET Framework, .NET Core, .NET 6+, and ASP.NET Core. - Strong experience developing RESTful APIs and ASP.NET Core Web APIs. - Strong experience with Entity Framework / Entity Framework Core. - Strong experience with SQL Server, including database development and performance considerations. - Strong understanding of Object-Oriented Programming (OOP), SOLID principles, design patterns, and clean-code practices. - Proven experience developing and maintaining enterprise-level business applications. - Strong debugging, troubleshooting, analytical, and problem-solving skills. - Ability to understand existing codebases and work effectively on established enterprise applications. - Ability to work independently, manage priorities, and take ownership of assigned development tasks. - Strong written and spoken English communication skills (C1/C2 level). - Ability to communicate technical concepts clearly with both technical and non-technical team members. 3. Preferred Qualifications - Experience with Microsoft Azure or other cloud platforms. - Experience designing or working with Microservices architectures. - Experience with Angular, React, or other modern frontend frameworks. - Experience with CI/CD pipelines, Azure DevOps, Git, and DevOps practices. - Experience with enterprise application modernization or migration from legacy .NET technologies. - Experience working with large-scale, high-volume, or business-critical applications. - Experience participating in technical architecture and system design. - Experience working in long-term product development teams. 4. Engagement Details - Long-term collaboration opportunity - Remote position - Up to 40 hours per week, depending on project requirements - Consistent weekly availability preferred - Flexible remote working arrangement - Ongoing development and maintenance of enterprise software - Opportunity for continued collaboration based on performance and project needs 5. Application Requirements To be considered, please provide all of the following: 1) Resume Please submit your latest resume highlighting your C#/.NET experience and relevant enterprise development projects. 2) Introduction Video Please provide a 1–2 minute video introduction in English. In the video, briefly: Introduce yourself and your professional background. Summarize your C#/.NET experience. Describe one recent enterprise project you personally worked on. Mention the technologies you used and your specific responsibilities. 3) Availability Please indicate: How many hours per week you can consistently commit Your general working hours/time zone When you would be available to start 4) Technical Screening Questions Please answer the following questions in your proposal: A. How many years of hands-on professional experience do you have with C# and .NET? B. What versions of .NET have you worked with most recently? C. Describe your experience developing ASP.NET Core Web APIs and RESTful services. D. Describe a technically difficult C#/.NET problem you personally solved. What was the problem, how did you investigate it, and what was the outcome? E. Describe your experience with Entity Framework/EF Core and SQL Server in production applications. F. Have you worked with Azure, Microservices, CI/CD, Angular, or React? Please specify which technologies you have used professionally and how. 5) Important Please do not submit a generic proposal. We are specifically looking for an experienced engineer with strong hands-on C#/.NET expertise and proven enterprise application experience. Applications that do not include a relevant resume, required introduction video, project examples, and answers to the technical screening questions may not be considered. Selected candidates will be invited to a technical discussion to further evaluate technical skills, communication, problem-solving ability, and overall project alignment. We are looking for someone interested in building a long-term working relationship, not a short-term one-off project.