Principal Software Engineer / Lead (.NET)

Distributed systems; microservices and modular monoliths; domain-driven design; event-driven architecture; API-first and contract-driven design; integration and messaging patterns; CQRS; resilience patterns (retry, circuit breaker, bulkhead, idempotency). This is our most senior individual contributor engineering role: Set architectural direction, raise the engineering bar across multiple teams, and lead platform modernization — while remaining hands-on in design, code, and critical problem-solving.

Our client, a Waste Disposal company, is looking for a Principal Software Engineer / Lead (.NET) for their Windsor, CT/Hybrid location.
 
Responsibilities:

• Client is seeking a Principal Software Engineer (.NET) to provide technical leadership across our enterprise application landscape.
• This is our most senior individual contributor engineering role:  Set architectural direction, raise the engineering bar across multiple teams, and lead platform modernization — while remaining hands-on in design, code, and critical problem-solving.
• Will pair deep Microsoft-stack expertise with strong systems architecture judgment, translating business strategy into scalable, secure, and maintainable technical solutions.
• Success in this role is measured less by what you build personally and more by the leverage you create: better architecture, faster and safer delivery, and a stronger engineering organization.
• Scope: Impact spans multiple teams, systems, and product lines — not a single application or squad.
• Ambiguity: Operates effectively on problems that are undefined, contested, or cross-organizational; frames the problem before solving it.
• Autonomy: Sets technical direction with minimal oversight; is accountable for outcomes, not tasks.
• Hands-on balance: Approximately [50–60%] architecture, design, technical leadership, and mentorship; [40–50%] hands-on engineering — prototypes, critical-path code, complex debugging, and reference implementations.
• Decision rights: Owns or co-owns architecture decisions; contributes to enterprise standards through the Architecture Review Board / equivalent forum.
• Performance Milestones:
• Timeframe
• Expected Outcomes
• First 30 Days:
• Build relationships across engineering, products, security, and infrastructure.
• Develop a working map of the current architecture, delivery pipeline, and pain points.
• Deliver an initial observations summary.
• First 90 Days:
• Publish an assessment of architectural risk and technical debt with a prioritized remediation view.
• Lead at least one architecture decision end-to-end. Establish a recurring design-review cadence.
• First 6 Months:
• Own a published, socialized technical roadmap for [platform/domain].
• Drive measurable improvement in at least two engineering health metrics.
• Establish standards adopted by multiple teams.
• First 12 Months:
• Demonstrate delivery of a major modernization milestone.
• Evidence of raised engineering capability through mentorship and standards adoption.
• Recognized as a trusted technical advisor by senior business and technology leadership.
• Architectural quality and consistency across supported platforms (e.g., reduction in bespoke integration patterns, standards adoption rate).
• Delivery health: DORA metrics — deployment frequency, lead time for change, change failure rate, mean time to restore.
• Reliability: attainment of agreed SLOs, reduction in Sev-1/Sev-2 incident volume and recurrence.
• Modernization progress: percentage of workload migrated off legacy .NET Framework; measurable technical debt reduction.
• Security posture: reduction in critical/high vulnerabilities, remediation cycle time, secure-by-design adoption.
• Talent impact: growth of senior engineers mentored, quality of design reviews, internal knowledge artifacts produced.
• Cloud efficiency: cost-per-transaction or infrastructure spend trend against workload growth.
• Technical Leadership:
• Serve as a technical leader and trusted advisor across multiple engineering teams.
• Establish and promote engineering standards, architectural principles, and development best practices.
• Lead technical reviews, architecture discussions, and strategic technology decisions.
• Drive consistency in software design, implementation, deployment, and operational practices.
• Provide guidance on complex technical and business challenges, including production escalations of significant business impact.
• Document and defend significant decisions through Architecture Decision Records (ADRs) and design documents.
• Architecture & Solution Design:
• Design scalable, resilient, and maintainable enterprise solutions using modern .NET technologies.
• Define application architecture, integration patterns, system boundaries, and service ownership models.
• Lead architectural governance and ensure alignment with enterprise technology standards.
• Evaluate emerging technologies and recommend adoption strategies grounded in cost, risk, and organizational readiness.
• Drive long-term technical roadmaps aligned with business objectives and funding cycles.
• Perform architecture risk assessments, including threat modeling and failure-mode analysis for critical systems.
• Modernization & Platform Evolution:
• Lead modernization of legacy .NET Framework applications and migration to modern .NET platforms.
• Drive adoption of cloud-native architectures, microservices, event-driven systems, and API-first design — applying each where justified rather than by default.
• Identify and reduce technical debt through structured, business-justified modernization programs.
• Improve system scalability, performance, reliability, and maintainability.
• Define migration sequencing, coexistence patterns, and rollback strategies that protect business continuity.
• Software Engineering Excellence:
• Champion engineering quality through code reviews, design reviews, and technical mentorship.
• Promote clean architecture, SOLID principles, domain-driven design, and secure coding practices.
• Establish and improve automated testing, observability, and quality engineering practices.
• Mentor senior engineers, technical leads, and engineering managers; contribute to technical hiring and interview standards.
• Foster a culture of continuous improvement, blameless postmortems, and technical excellence.
• Platform Engineering & DevOps:
• Partner with infrastructure, platform, security, and operations teams to improve engineering productivity.
• Support implementation of self-service engineering capabilities and internal developer platform practices.
• Drive CI/CD standardization, automation, and deployment safety (progressive delivery, feature flags, automated rollback).
• Promote Infrastructure as Code and modern deployment practices.
• Ensure solutions meet reliability, security, compliance, and operational requirements, including SLOs and error budgets.
• Security, Risk & Compliance:
• [New — expected for a regulated-industry employer; confirm applicable frameworks.]
• Embed secure-by-design and privacy-by-design practices into architecture and delivery standards.
• Ensure solutions satisfy applicable regulatory and audit obligations
• Partner with Information Security on threat modeling, vulnerability management, identity and access architecture, and data protection.
• Contribute to disaster recovery and business continuity design, including RTO/RPO validation and resilience testing.
• AI-Assisted Engineering & Emerging Technology:
• Define standards for responsible use of AI coding assistants (e.g., GitHub Copilot) including review, security, and IP considerations.
• Evaluate and guide adoption of AI/GenAI capabilities within enterprise applications, including integration patterns, evaluation, and guardrails.
• Ensure AI-assisted development improves throughput without degrading code quality, security, or maintainability.
• Cross-Functional Collaboration:
• Collaborate with Product Management, Architecture, Security, Infrastructure, Data, and business stakeholders.
• Translate business goals into scalable technical solutions, and technical trade-offs into business terms.
• Participate in strategic planning, capacity forecasting, and technology investment decisions.
• Communicate architectural vision and technical direction to both technical and non-technical audiences, up to and including executive leadership.
• Support vendor and third-party technology evaluations where relevant.
• Leadership Traits & Behavioral Competencies:
• Core Leadership Expectations:
• Influence technical strategy beyond a single application or team.
• Drive architectural consistency across the organization.
• Establish engineering standards and governance that teams adopt willingly.
• Mentor and develop technical talent at senior and lead levels.
• Balance business priorities with long-term platform sustainability.
• Lead by example through hands-on technical contribution and architectural leadership.
• Influence Without Authority:
• Builds consensus across teams that do not report to them; wins adoption through clarity and credibility rather than mandate.
• Pragmatic Judgment:
• Chooses the appropriate solution for the context and constraints; resists over-engineering and technology fashion.
• Business Fluency:
• Frames technical decisions in terms of cost, risk, revenue, and time-to-market; understands the commercial context of the platform.
• Communication Range:
• Adjusts depth and language effectively from engineer to executive; writes clearly and persuasively.
• Mentorship & Multiplication:
• Measures success by the capability of others; delegates meaningful technical ownership rather than hoarding it.
• Ownership & Accountability:
• Takes responsibility for outcomes including failures; leads to blameless postmortems and drives corrective action.
• Continuous Learning:
• Stays current with the .NET and cloud ecosystem and shares knowledge systematically.

 
Requirements:

• Resilience Under Pressure:
• Remains calm and decisive during major incidents, escalations, and competing executive priorities.
• Languages & Frameworks (Core):
• C#; .NET 8 (LTS) and current .NET releases; ASP.NET Core; ASP.NET MVC; Web API; Entity Framework Core; async/concurrent programming; legacy .NET Framework (4.x) for modernization context
• Architecture (Core):
• Distributed systems; microservices and modular monoliths; domain-driven design; event-driven architecture; API-first and contract-driven design; integration and messaging patterns; CQRS; resilience patterns (retry, circuit breaker, bulkhead, idempotency)
• Cloud (Core):
• Microsoft Azure — App Service, Azure Functions, AKS, Service Bus / Event Hubs / Event Grid, API Management, Key Vault, Entra ID, Azure Monitor; landing zone and well-architected principles
• DevOps & Platform (Core):
• Azure DevOps and/or GitHub Actions; CI/CD pipeline design; Docker; Kubernetes; Terraform and/or Bicep; Git branching and release strategy; artifact and dependency management
• Data (Core):
• SQL Server; Azure SQL; performance tuning and query optimization; data modeling; NoSQL (e.g., Cosmos DB); caching (Redis); schema migration and zero-downtime data change strategy
• Quality & Operations (Core):
• Automated testing strategy (unit, integration, contract, end-to-end); test automation in CI; observability (Open Telemetry, Application Insights); logging, metrics, distributed tracing; performance and load engineering; incident response
• Security Engineering (Core):
• OAuth 2.0 / OpenID Connect; secrets management; secure SDLC; SAST/DAST/SCA tooling; threat modeling; encryption in transit and at rest; vulnerability remediation
• Supporting / Contextual:
• Front-end awareness (React / Angular / Blazor) sufficient to review full-stack designs; messaging platforms (Kafka, RabbitMQ); mainframe or legacy system integration; FinOps and cloud cost optimization; AI-assisted development tooling
• Required Qualifications:
• Bachelor’s degree in computer science, Engineering, or a related discipline — or equivalent practical experience.
• 15+ years of professional software engineering experience, with significant experience in enterprise application development.
• Deep expertise in C#, ASP.NET, ASP.NET Core, and modern .NET platforms.
• Demonstrated experience designing and implementing enterprise-scale distributed systems in production.
• Strong command of software architecture patterns and principles, with the judgment to know when not to apply them.
• Track record of leading technical initiatives across multiple teams without direct authority.
• Experience delivering cloud-based solutions in a production environment (Azure preferred).
• Strong problem-solving and analytical skills, including production incident diagnosis in complex systems.
• Excellent written and verbal communication skills, with the ability to influence senior stakeholders.
• Preferred Qualifications:
• Experience with cloud platforms, particularly Microsoft Azure, at enterprise scale.
• Knowledge of platform engineering and internal developer platforms.
• Experience with event-driven architecture and messaging platforms.
• Experience building highly available, mission-critical applications with defined SLAs/SLOs.
• Experience in insurance, financial services, healthcare, or another regulated industry.
• Experience leading large-scale legacy modernization or cloud migration programs end-to-end.
• Relevant certifications: Microsoft Certified Azure Solutions Architect Expert, Azure DevOps Engineer Expert, or equivalent.
• Experience with SRE practices — SLO definition, error budgets, and incident command.
• Contributions to open source, technical publications, conference speaking, or internal engineering communities.
• Experience in integrating AI/GenAI capabilities into enterprise applications.

 
Why Should You Apply?

• Health Benefits
• Referral Program
• Excellent growth and advancement opportunities