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Senior .Net Developer

Trillium Professional is now seeking a Senior .Net Developer in Everett, MA - Hybrid, one day per week. 

The Senior .NET Developer - Modernization Lead is responsible for driving architectural evolution, technical modernization, and delivery resilience across enterprise C#/.NET applications supporting critical business operations.

This role partners closely with Business Analysts, Product Owners, and technical leadership to design and implement secure, scalable, and maintainable solutions aligned with agency objectives. The position provides senior-level technical direction within an Agile environment, strengthens architectural standards, reduces legacy 
system risk, and improves system performance and operational reliability.

The Senior .NET Developer - Modernization Lead serves as a senior technical voice within the team. They influence design decisions, guide modernization strategy, and help distribute institutional knowledge to reduce single points of failure.

Position Duties/Responsibilities:
• Lead architectural design, development, and modernization efforts across C#/.NET applications.
• Provide technical ownership for modernization initiatives, including legacy refactoring, cloud-readiness, 
and system resiliency improvements.
• Partner with Business Analysts and Product Owners to translate complex business requirements into 
scalable technical solutions.
• Establish and enforce architectural standards, coding guidelines, and design patterns across the 
application stack.
• Drive reduction of technical debt and systemic risk through structured remediation planning.
• Guide cross-team technical coordination where services or integrations intersect.
• Mentor engineers through design reviews, code reviews, and modernization best practices.
• Design, implement, and govern secure, scalable RESTful APIs and backend services.
• Lead root-cause analysis of complex production issues and implement durable corrective solutions.
• Collaborate with QA and DevOps to improve automation, release quality, observability, and deployment 
confidence.
• Contribute to operational readiness planning, monitoring strategies, and production stability efforts.
• Identify and proactively mitigate architectural and delivery risks.

Pay rate is $76/hour! Apply now!

Minimum Qualifications (Please add minimum education requirement here):
• Bachelor’s degree in Computer Science, Information Systems, Engineering, or related technical field, or 
equivalent professional experience.
• 7+ years of professional experience developing enterprise applications using C# and .NET (Framework 
and .NET Core / .NET 8/9+ preferred).
• Demonstrated experience leading or owning architectural decisions in complex or legacy environments.
• Strong expertise with ASP.NET MVC and API-driven architectures.
• Advanced experience with Microsoft SQL Server (2012+), including performance tuning, indexing 
strategies, and query optimization.
• Demonstrated success modernizing legacy systems, including refactoring monolithic architectures and 
improving maintainability.
• Experience designing secure, scalable RESTful APIs with strong authentication and authorization 
patterns (JWT, OAuth, claims-based security).
• Experience implementing structured logging, monitoring, and observability solutions in production 
environments.
• Strong knowledge of dependency injection, middleware pipelines, async/await, background services, 
and distributed processing.
• Working knowledge of SPA architecture and modern frontend frameworks (Angular or React).
• Experience influencing technical standards or mentoring developers within an Agile environment.
• Proficiency with Git-based source control and CI/CD automation.
• Demonstrated ability to identify systemic risk and deliver durable, maintainable technical solutions.

Preferred Qualifications:
• Experience operating in matrixed, cross-agency, or public-sector environments.
• Experience leveraging LLMs and automation tools to improve engineering productivity.
• Familiarity with cloud platforms and cloud-native architectures.

Special Requirements and/or Specifications for the Posting:
• Demonstrable senior-level experience modernizing legacy .NET systems (.NET Core/6+/Cloud)
• Proven ownership, autonomy, and delivery accountability
• Advanced SQL Server performance tuning (indexing, execution plans, deadlock analysis)
• Experience in public-sector / regulated environments (CJIS, HIPAA, FERPA, SOC2, etc.) preferred
• Ability to lead technical design and mentor junior developers

 

Trillium has been recruiting and placing professionals for over 30 years. From Fortune 100 companies to small businesses, our philosophy remains the same: to achieve excellence by providing quality employees and an uncompromising level of service. We believe in honesty, integrity, and a simple philosophy of providing value to our customers and our employees. We strive to be unsurpassed in the recruitment and placement of quality and skilled professionals. Trillium is an Equal Opportunity Employer.

Qualified applications with arrest or conviction records will be considered for employment in accordance with the Los Angeles County Fair Chance Ordinance for the employers and the California Fair Chance Act.

By applying to this job, I agree to receive electronic communications including SMS text and email regarding future opportunities, referral bonus incentives, and other promotions from Trillium. You may opt out at any time from future communications by responding STOP to any electronic communication. You may view our full privacy policy at https://trilliumstaffing.com/jobs/privacy/.

Trillium offers a comprehensive benefit package that includes the ability to participate in health insurance and retirement plans, paid holidays, state required leave, and vacation days, if applicable. Trillium’s offerings are dependent on the state in which the assignment is located, length of time worked, and may change depending on assignment. Benefit packages for direct hire placements vary based on the client company.

 

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