Senior .NET Developer (Legacy Systems & Application Architecture)

Job Summary

Role Type: Contract Experience: 10-15 years. About the Role Were looking for a hands-on Senior .NET Developer to take ownership of a mission-critical legacy application built on .NET Web Forms and jQuery, backed by SQL Server. This role requires someone who can operate independently, quickly build a working mental model of an existing codebase, and immediately start contributing to active development and support work - with minimal ramp-up supervision.

Responsibilities

• Take ownership of ongoing development, enhancement, and support of a .NET Web Forms application with C# and jQuery.
• Analyze and troubleshoot complex technical issues across the application stack, including the database layer.
• Independently pick up assigned features/bugs, estimate effort, and deliver high-quality, tested code within committed timelines.
• Apply practical AI/automation tools (e.g., Copilot-style coding assistants, scripted automation, LLM-assisted debugging/documentation) to speed up development, testing, and support turnaround.
• Collaborate directly with business and technical stakeholders to clarify requirements and align on design decisions.
• Document system behavior and architectural decisions as understanding is built, to reduce single-person dependency risk.
• Proactively flag technical debt, risks, or performance issues in the legacy codebase.

Required Experience / Skills

• 8+ years hands-on development experience in .NET (C#), ASP.NET Web Forms, and jQuery.
• Excellent understanding of relational databases and strong SQL skills - writing/optimizing queries, working with stored procedures and functions, and reasoning about schema and data flow.
• Demonstrated ability to work independently on legacy systems with minimal documentation or handover support.
• Practical experience using AI coding/productivity tools (Copilot, ChatGPT/Claude for code review, automation scripting, etc.) in a real delivery context.
• Strong debugging and root-cause analysis skills across full-stack issues.
• Proven track record of consistent, on-time, quality delivery - able to speak with specific examples.
• Strong communication skills; comfortable interfacing directly with both business and technical stakeholders.

Nice to Have

• Exposure to SSIS (ETL package development/support) and SSRS (report development/maintenance).
• Prior experience modernizing or maintaining legacy Web Forms applications.
• Exposure to system integration (APIs, third-party services, data feeds).
• General familiarity with data warehouse concepts.
• React JS (Near Future development).

What Success Looks Like in This Role

• Rapid ramp-up: functional understanding of the existing system within ~4 weeks.
• Independent ownership of development/support tickets with minimal escalation.
• Measurable improvement in turnaround time on support/enhancement requests, partly through applied AI/automation practices.
• Reliable, self-driven delivery without requiring close oversight.

Disclaimer: This job posting has been aggregated from external source. Role details, content, and availability are subject to change. Applicants are advised to confirm the latest information directly on the company website before applying.