Senior C# Developer

AllSTEM Connections; Westford (MA); On-site; USD 120,000 - 160,000; Full time

Job summary

AllSTEM Connections is seeking a Senior C# Software Engineer in Westford, MA to design, build, and maintain high-performance Windows applications and own the full release lifecycle, including packaging and deployment automation.

The role requires hands-on development with .NET technologies, strong expertise in installer tooling, and leadership in CI/CD practices. You will mentor juniors and drive architectural decisions while collaborating with QA and product teams.

Qualifications

• Minimum 5–7 years of C# development in Windows environments.
• Hands-on expertise with .NET Framework, .NET Core, and Windows Services.
• Deep knowledge of installer tech: Advanced Installer and WiX Toolset.
• Experience managing full release lifecycles: patches, upgrades, silent installs.
• Strong CI/CD experience and PowerShell scripting.
• Ability to mentor juniors and lead technical initiatives.

Responsibilities

• Design, develop, test, and maintain high-performance Windows applications.
• Lead architecture discussions and review code.
• Create, maintain MSI installers and bootstrapper packages.
• Design and implement upgrade, patching, rollback, and migration strategies.
• Build and sustain CI/CD pipelines (GitHub Actions) and automate deployments.
• Provide production support and resolve installation issues.
• Collaborate with QA and product teams to ensure release readiness.

Skills

.NET Framework

.NET Core

Windows Services

WiX Toolset

Advanced Installer

MSI Packaging

PowerShell

CI/CD Pipelines

Release Engineering

Technical Leadership

Azure

AWS

Docker

Kubernetes

Blazor

Troubleshooting

Tools

GitHub Actions

Job description

Job Title: Senior C# Software Engineer (Windows Applications & Release Engineering)

Role Overview

We are seeking a highly skilled, hands-on Senior C# Developer to design, build, and maintain scalable, high-performance applications that power our critical business functions. In this role, you will lead the evolution of our application architecture while taking ownership of the full software release lifecycle-from core development and patching strategies to sophisticated installer packaging and deployment.

This is a senior-level technical role that balances high-level architecture decisions with low-level release engineering. You will collaborate closely with QA and product teams to build reliable upgrade, migration, and rollback strategies, mentor junior team members, and drive CI/CD excellence. If you are a release-focused developer who understands the complexities of Windows environments and deployment automation, we want to hear from you.

Key Responsibilities

Development & Architecture

Application Engineering: Design, develop, test, and maintain robust, high-performance applications using C# and modern .NET technologies (Framework and Core).

Technical Leadership: Act as a senior contributor and technical mentor; conduct code reviews, influence architectural strategies, and drive technical decision-making.

Release Engineering & Installer Packaging

Advanced Packaging: Create, maintain, and troubleshoot complex MSI installers and bootstrapper applications utilizing tools such as WiX Toolset and Advanced Installer.

Deployment Strategy: Design end-to-end upgrade, patching, rollback, and migration strategies. Develop specialized packages for hotfixes, upgrades, and silent installations.

Pipeline Management: Build and manage CI/CD pipelines (e.g., GitHub Actions) and utilize PowerShell scripting to ensure reliable, automated deployment processes.

Quality & Troubleshooting

Production Support: Analyze and resolve complex production issues and installation-related roadblocks, ensuring software quality and release readiness.

Continuous Improvement: Work in tandem with QA teams to ensure software quality and contribute to the evolution of release management standards.

Qualifications & Requirements

Minimum Qualifications

Experience Baseline: Minimum of 5 to 7 years of professional experience in C# software development, specifically within Windows environments.

Technical Mastery

• oExtensive hands-on experience with .NET Framework, .NET Core, and Windows Services.
• oDeep expertise in Installer Technologies: Advanced Installer, WiX Toolset, MSI package creation, and Bootstrapper applications.
• oProven experience managing the full release lifecycle (patches, hotfixes, silent installs, and upgrade packages).
• oStrong working knowledge of Windows Installer internals and deployment troubleshooting.
• oHands-on experience with Release Engineering: CI/CD pipeline management and PowerShell scripting.

Core Competencies: Strong analytical, problem-solving, and communication skills; ability to partner cross-functionally in a fast-paced environment; experience mentoring junior developers.

Preferred Attributes

Experience with cloud platforms (Azure or AWS) and containerization (Docker, Kubernetes).

Knowledge of microservices architecture, event-driven systems, or distributed computing.

Familiarity with frontend frameworks (Angular, React, or Blazor).

Understanding of DevOps practices, Infrastructure as Code (IaC), and automated testing.

Previous experience leading technical initiatives or small development teams.

Equal Opportunity Employer / Disabled / Protected Veterans

The Know Your Rights poster is available here:

_EEOC_KnowYourRights6.12.pdf

The pay transparency policy is available here:

_%20English_formattedESQA508c.pdf

For temporary assignments lasting 13 weeks or longer, AllSTEM Connections is pleased to offer major medical, dental, vision, 401k and any statutory sick pay where required.

We are committed to working with and providing reasonable accommodations to individuals with disabilities. If you need a reasonable accommodation for any part of the employment process, please contact your staffing representative who will reach out to our HR team.

AllSTEM Connections participates in the E-Verify program in certain locations as required by law. Learn more about the E-Verify program.

_Participation_Poster_ES.pdf

We also consider for employment qualified applicants regardless of criminal histories, consistent with legal requirements, including, if applicable, the City of Los Angeles' Fair Chance Initiative for Hiring Ordinance. Pursuant to applicable state and municipal Fair Chance Laws and Ordinances, we will consider for employment-qualified applicants with arrest and conviction records, including, if applicable, the San Francisco Fair Chance Ordinance. For Los Angeles, CA applicants: Qualified applications with arrest or conviction records will be considered for employment in accordance with the Los Angeles County Fair Chance Ordinance for Employers and the California Fair Chance Act.

Additional Skills

(none specified)