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Principal .NET / C# Engineer

Westford, MA, US • Posted 6 hours ago • Updated 19 minutes ago

Contract W2

Travel Required

On-site

Fitment

Dice Job Match Score™

👾 Reticulating splines...

Job Details

Skills

.net
backend
core
ADO.NET
Copilot

Summary

Sr Principal Engineer

Westford MA USA 01886

Description:

We are seeking a highly experienced Sr. Principal C#/.NET Engineer to support the development and modernization of the Crossfire security integration platform. This is a senior technical role focused on hands-on engineering, architectural refinement, deep debugging, and accelerating delivery of high priority features.
The ideal candidate is a seasoned engineer who thrives in complex systems, understands secure real time communication patterns, and can quickly become productive in a large-scale, mission-critical codebase.

Key Responsibilities

Serve as a principal-level contributor on the Crossfire engineering team, supporting core platform enhancements and maintenance.
Design, implement, and optimize high performance C#/.NET services, frameworks, and integration components.
Work on event-driven, multi-threaded, and distributed system patterns within the Crossfire platform.
Troubleshoot and resolve complex bugs, performance bottlenecks, and reliability issues across the system.
Contribute to architectural improvements, refactoring efforts, and modernization of legacy components.
Collaborate with product owners, architects, and QA to ensure high-quality releases and technical consistency.
Develop clear technical documentation for system components, APIs, interfaces, and deployment processes.
Mentor team members and provide technical leadership where necessary.

Required Qualifications

7-10 years of professional software engineering experience.
Expert-level proficiency in C#, .NET Framework/.NET Core, and advanced debugging techniques.

Strong experience with:

Multi-threaded programming
Event-driven or message-based architectures
Windows services and system-level programming
Networking protocols, sockets, and real-time communications
Copilot AI and different models
Proven ability to quickly understand and contribute to large, existing codebases.
Experience building highly reliable, fault-tolerant backend services.
Demonstrated ability to work independently in a contract environment with minimal ramp-up time.
Excellent problem-solving skills and strong written communication/documentation ability.

Preferred Qualifications:

Experience with access control/security integration platforms, or similar real-time device/customer integration systems.

Experience with:

SQL Server and data access layers (ADO.NET, EF, stored procedures)
Diagnostic tooling, memory profiling, and performance analysis
REST APIs, SOAP, or custom protocol integrations
Modern DevOps, CI/CD pipelines (Azure DevOps, GitHub Actions, etc.)
Analyzing Windows Memory dumps

Employers have access to artificial intelligence language tools (“AI”) that help generate and enhance job descriptions and AI may have been used to create this description. The position description has been reviewed for accuracy and Dice believes it to correctly reflect the job opportunity.

Dice Id: 91082005
Position Id: 2026-25419/136740
Posted 6 hours ago

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