Principal Software Engineer - Medical Devices & Secure AI

Connexion Systems + Engineering; Marlborough (MA); On-site; USD 180,000 - 200,000; Full time

Job summary

Connexion Systems & Engineering Inc. seeks a Principal Software Engineer to lead the design and delivery of advanced software across web, mobile and service ecosystems.

The role requires deep expertise in C#/.NET, modern front‑end and server‑side technologies, and collaboration with architects and stakeholders. The ideal candidate will drive secure coding practices, threat modeling, and software supply chain integrity while mentoring engineers and guiding platform evolution in a regulated

Qualifications

• Bachelor's degree in Computer Science, Software Engineering or related field.
• 8+ years of software engineering experience.
• 3+ years developing for medical devices (ISO 14971/13485/62304).
• Solid understanding of software development lifecycle models, including Agile delivery.
• Proficient in C#/.NET and HTML/CSS/JS or TypeScript.
• Extensive knowledge of object‑oriented programming and distributed systems design.
• Strong cybersecurity knowledge including Secure SDLC and threat modeling.
• Embedded/firmware experience with C/C++, RTOS and hardware‑in‑the‑loop testing.
• Experience with NUnit/MSTest or similar unit testing frameworks and CI/CD gates.
• Excellent problem solving, communication and mentoring skills.

Responsibilities

• Provide technical leadership for design, implementation and maintenance of complex software systems across the connected device ecosystem.
• Define and evolve a vision of scalable, reliable, secure and maintainable software solutions.
• Create and maintain software architecture and design documentation, including design controls and traceability records for regulated products.
• Identify opportunities for optimization in terms of performance, cost, reliability and resource utilization.
• Deliver hands-on development of responsive, user-friendly web applications, services and APIs.
• Collaborate with UX/UI designers to translate designs into high-quality, accessible code.
• Drive engineering standards, code quality and secure coding practices, and lead code reviews.
• Champion secure-by-design and threat modeling across products and govern software supply chain integrity via SBOMs and vulnerability response.
• Guide the adoption of AI-enabled capabilities with guardrails and human-in-the-loop practices for regulated products.
• Mentor engineers and technical leads, and provide onboarding guidance.
• Stay up to date with emerging trends in web, application and AI development.

Skills

Software architecture

Technical leadership

C#/.NET development

Web/mobile/API development

Cybersecurity awareness

AI-enabled capabilities

Mentoring

Education

Bachelor's degree in CS/Software Eng or related field

Tools

CI/CD tools

Cloud platforms (Azure/AWS/GC)

Job description

Connexion Systems & Engineering Inc. seeks a Principal Software Engineer to lead the design and delivery of advanced software across web, mobile and service ecosystems.

The role requires deep expertise in C#/.NET, modern front‑end and server‑side technologies, and collaboration with architects and stakeholders. The ideal candidate will drive secure coding practices, threat modeling, and software supply chain integrity while mentoring engineers and guiding platform evolution in a regulated