Senior Full Stack Software Engineer – C#/.NET | Medical Devices

Connexion Systems + Engineering; Northborough (MA); Hybrid; USD 160,000 - 180,000; Full time

Job summary

Connexion Systems & Engineering is seeking a Senior Full Stack Software Engineer to join our growing software team in the medical device space. You will work across the full stack, building secure, scalable applications that interface with connected devices.

The role emphasizes hands-on coding with C#/.NET, modern front-end tech, and strong architecture experience. The position is hybrid in Northborough, MA (3 days on-site, 2 days remote), offering competitive compensation ($160,000–$180,000+

Qualifications

• 5+ years of professional full-stack software development experience.
• Strong hands-on proficiency in C#/.NET development.
• Experience with HTML, CSS, JavaScript, and TypeScript.
• Experience with modern front-end frameworks; Blazor desirable.
• Experience designing, developing, and integrating RESTful APIs and backend services.

Responsibilities

• Design, develop, and maintain responsive web applications, backend services, and APIs using C#/.NET and front-end technologies.
• Develop modern front-end applications with Blazor and other frameworks.
• Build and integrate APIs and services for communication with device controllers and connected systems.
• Collaborate with UX/UI designers to translate wireframes into high-quality applications.
• Optimize performance, scalability, reliability, and maintainability; troubleshoot complex issues.

Skills

C#/.NET

Front-end development

Blazor

RESTful APIs

MVC/MVVM

Git

Agile/Scrum

Secure SDLC

Education

Bachelor's degree in Computer Science, Software Engineering, or related field

Tools

Git

Cloud platforms (Azure/AWS/GCP)

Job description

Senior Full Stack Software Engineer – C#/.NET | Medical Devices

Hiring Organization: Connexion Systems & Engineering

Pay: $160,000–$180,000+ annually, DOE

Employment Type: Full-Time, Direct Hire

Job Location: Northborough, MA

Work Model: Hybrid – 3 Days On-site / 2 Days Remote

Schedule: Monday – Friday, 1st shift; Job #: bh19871

Work Authorization & Location Requirements: Candidates must be currently authorized to work in the United States without employer sponsorship, now or in the future. This position is not eligible for visa sponsorship, including employment under CPT or OPT authorization. Candidates must be able to work on-site in Northborough, MA, 3 days per week. Travel expenses will not be reimbursed. Relocation assistance is not available. Candidates must reside within commuting distance or be willing to relocate at their own expense.

We are seeking an experienced Senior Full Stack Software Engineer to join a growing software engineering team developing innovative applications and connected technologies for the medical device industry. This is an opportunity for a hands‑on engineer with strong C#/.NET expertise, modern front‑end development experience, and a solid understanding of software architecture and design principles. The ideal candidate enjoys working across the full technology stack, from building responsive user interfaces to developing backend services and APIs that communicate with connected medical devices. You'll collaborate with software architects, UX/UI designers, product stakeholders, and engineering teams to develop scalable, secure, and reliable applications in a regulated environment.

Key Responsibilities

• Design, develop, and maintain responsive web applications, backend services, and APIs using C#/.NET, HTML, CSS, JavaScript, and/or TypeScript.
• Develop modern front‑end applications using contemporary frameworks, ideally including Blazor.
• Build and integrate APIs and services that support communication with device controllers and connected medical devices.
• Collaborate with UX/UI designers to translate wireframes, prototypes, and technical requirements into accessible, high‑quality applications.
• Optimize applications for performance, scalability, reliability, and maintainability.
• Troubleshoot and resolve complex technical issues across front‑end, backend, and service layers.

Software Engineering & Architecture

• Apply object‑oriented programming principles and established software design patterns, including MVC, MVVM, and Dependency Injection.
• Write clean, maintainable, well‑documented code while contributing to engineering standards and best practices.
• Participate in architectural discussions, technical design reviews, and code reviews.
• Mentor junior engineers and collaborate with cross‑functional development teams.
• Work within Agile/Scrum environments using Git and modern development workflows.

Medical Device Software & Cybersecurity

• Develop and maintain software supporting regulated medical devices, following applicable standards such as IEC 62304.
• Create and maintain software design documentation, traceability records, and supporting verification and validation artifacts.
• Apply secure software development lifecycle (Secure SDLC) principles, including secure coding, threat modeling, and vulnerability remediation.
• Support automated testing, continuous integration, and software quality initiatives.
• Incorporate cybersecurity best practices, including dependency management, vulnerability scanning, and software supply chain security.

Emerging Technologies & Integration

• Evaluate opportunities to incorporate AI‑enabled and agentic capabilities into software applications.
• Support emerging AI technologies, including retrieval‑augmented generation (RAG), tool calling, guardrails, and human‑in‑the‑loop workflows.
• Collaborate on integrations involving connected devices, embedded systems, and firmware interfaces.
• Stay current with emerging technologies in web development, cloud computing, application security, and AI.

Required Qualifications

• 5+ years of professional full-stack software development experience, with a focus on front‑end applications and backend services.
• Strong hands‑on proficiency in C#/.NET development.
• Experience developing modern web applications using HTML, CSS, JavaScript, and/or TypeScript.
• Experience with modern front‑end technologies and frameworks; Blazor experience is highly desirable.
• Experience designing, developing, and integrating RESTful APIs, web services, and backend applications.
• Strong understanding of object‑oriented programming, software engineering principles, and design patterns, including MVC, MVVM, and Dependency Injection.
• Experience using Git, Agile methodologies, and Scrum development practices.
• Knowledge of software development for regulated medical devices, including IEC 62304, design controls, and requirements traceability.
• Understanding of secure coding practices, cybersecurity principles, and the Secure SDLC.
• Strong debugging, troubleshooting, and problem‑solving abilities.
• Excellent communication and collaboration skills, with the ability to work effectively across engineering disciplines.
• Bachelor's degree in Computer Science, Software Engineering, or a related field, or equivalent professional experience.

Additional Experience of Interest

• Blazor and other modern .NET front‑end technologies.
• Cloud platforms such as Microsoft Azure, AWS, or Google Cloud.
• Containerization, CI/CD pipelines, and automated testing frameworks.
• Medical device software verification, validation, and regulatory documentation.
• OWASP ASVS, threat modeling, dependency scanning, and software bills of materials (SBOMs).
• Connected device integration, device communication protocols, and firmware interfaces.
• Embedded development using C/C++, RTOS, or hardware‑in‑the‑loop testing.
• AI‑enabled application development, including agentic AI, RAG, tool orchestration, evaluation, and AI governance.
• Mobile application development and responsive UI/UX design.

What We're Looking For

The successful candidate will be a strong, hands‑on C#/.NET engineer who enjoys building software across the full stack and solving complex technical challenges. We're particularly interested in engineers who combine modern web application development with backend service integration and an understanding of the quality, documentation, and security requirements associated with medical device software. This role is ideal for someone who enjoys collaborating with technical teams, contributing to architectural decisions, mentoring other developers, and delivering reliable software that supports real‑world medical technologies.

Work Arrangement

This is a hybrid position based in Northborough, MA requiring 3 days on‑site and allowing 2 days of remote work each week.