Principal Software Engineer

Telguard is seeking an accomplished Principal Software Engineer to provide hands-on technical leadership for enterprise web applications built with C# and .NET Core. This role will shape application architecture, establish engineering standards, and guide the design, development, testing, deployment, and support of secure, reliable software used by internal teams, customers, and external partners. The Principal Software Engineer will work across web applications, back-office services, APIs, and Microsoft SQL Server data solutions that support Telguard cellular alarm communicators and the processing of alarm events from security and fire alarm systems. The role partners closely with Product Management, Quality Assurance, other engineering disciplines, Technical Support, Customer Service, and operational stakeholders. Key Responsibilities: Define and evolve the architecture of scalable, maintainable, and secure web applications and services using C# and .NET Core. Lead technical design for integrations, RESTful APIs, back-office processing, and customer-facing web capabilities, including solutions that create or consume JSON and XML. Provide hands-on engineering leadership through complex feature implementation, prototypes, code reviews, troubleshooting, and the resolution of high-impact technical issues. Design and optimize Microsoft SQL Server solutions, including relational data models, queries, indexing strategies, transactions, and SQL stored procedures. Establish and promote software engineering standards for application design, coding, source control, automated testing, security, observability, documentation, and supportability. Guide modernization of existing applications and services, including pragmatic migration to current .NET Core technologies and modern web application patterns. Partner with Quality Assurance to improve test strategy, automated test coverage, release confidence, and defect prevention. Own technical quality across the delivery lifecycle, from requirements and architecture through deployment, production monitoring, incident analysis, and continuous improvement. Strengthen build and release practices using Azure Pipelines and Octopus Deploy, and support reliable application hosting and configuration in IIS. Mentor software engineers, facilitate technical decision-making, and raise the engineering capability of the team through clear guidance and knowledge sharing. Collaborate with Product Managers and business stakeholders to translate product goals and operational needs into sustainable technical solutions. Evaluate frameworks, tools, and design alternatives, balancing delivery speed with security, performance, reliability, maintainability, and total cost of ownership. Demonstrated ability and willingness to use AI tools to improve productivity, decision-making, work quality, and to reduce costs. The successful candidate must be able to identify appropriate AI use cases and critically evaluate AI-generated outputs. Technical Skills: Required Skills .NET Core and C# Microsoft SQL Server and advanced SQL SQL stored procedure design, development, tuning, and troubleshooting Enterprise web application architecture and development RESTful API design and integration Object-oriented design, design patterns, and clean-code practices Automated testing, debugging, and performance analysis Secure software development and application lifecycle practices Other Relevant Skills Azure Pipelines for continuous integration and delivery Octopus Deploy for release automation and environment promotion Internet Information Services (IIS) administration, hosting, and troubleshooting HTML, CSS, JavaScript, and modern web application frameworks Git-based source control and branching strategies Application logging, monitoring, observability, and production support JSON and XML integrations Cloud or hybrid application deployment patterns Qualifications and Experience: Bachelor’s degree in Computer Science, Software Engineering, Computer Engineering, or a related discipline, or equivalent practical experience. Extensive professional experience designing and delivering production software, with significant depth in C#, .NET Core, web applications, and Microsoft SQL Server. Demonstrated success serving as a technical lead or principal-level engineer for complex, business-critical systems. Proven ability to make sound architectural decisions, communicate tradeoffs, and lead implementation across multiple engineers or workstreams. Strong experience diagnosing reliability, security, performance, data, deployment, and integration issues across application tiers. Experience partnering with cross-functional teams and communicating technical concepts clearly to both technical and non-technical stakeholders.