Principal Applications & Systems Engineer – .NET, PHP & AI (Louisville Metropolitan Area)

Location: Jeffersonville, Indiana (On-site)

Salary: $160,000–$185,000 annually

Employment Type: Full-time

Position Overview: Black Diamond Pest Control is seeking an experienced, hands-on Principal Applications & Systems Engineer to develop, maintain, and modernize our internal business applications and supporting technology infrastructure. This is a highly technical position for someone who enjoys writing code, designing applications, managing databases, troubleshooting complex systems, and implementing emerging technologies. Our environment includes custom applications developed in C#, .NET Core / ASP.NET Core, Blazor, and PHP, along with PostgreSQL and MySQL databases, Linux and Windows servers, virtualization, and enterprise networking. We are also actively exploring how artificial intelligence and automation can improve our business operations, customer interactions, reporting, and internal workflows. The successful candidate will help evaluate and integrate these technologies into our existing applications and infrastructure. This is a hands-on engineering and development position, not a traditional IT management role. We want someone who enjoys building and improving technology directly rather than managing teams or delegating technical work.

Application Development & Modernization: Design, develop, maintain, and enhance business-critical applications using C#, .NET Core / ASP.NET Core, and PHP.Contribute directly to the continued modernization of our internal CRM and operational applications. Develop modern web applications using Blazor and related .NET technologies. Maintain and enhance existing PHP applications, including Linux-hosted web applications. Design and develop REST APIs, background services, and integrations between internal and third-party systems. Refactor and improve existing application code to increase performance, security, reliability, and maintainability. Troubleshoot complex application issues across frontend, backend, database, and infrastructure layers. Participate in application architecture, code reviews, testing, and deployment processes. Develop scripts, utilities, and automated processes to reduce repetitive work.

Database Engineering & Optimization: Develop and optimize SQL queries, stored procedures, and database-driven application functionality. Work extensively with PostgreSQL and MySQL databases. Diagnose and resolve database performance, indexing, locking, and connectivity issues. Support database architecture, maintenance, backup, recovery, and reliability. Improve application and database performance through effective design and troubleshooting.

Infrastructure & Systems Engineering: Administer and troubleshoot Linux and Windows server environments. Support virtualized infrastructure, preferably using KVM or comparable technologies. Maintain application hosting environments, including web servers, reverse proxies, and associated services. Troubleshoot networking, firewalls, routing, DNS, storage, and system security issues. Maintain and improve backup, disaster recovery, monitoring, and business continuity systems. Automate infrastructure and operational tasks using scripting and other appropriate technologies. Ensure reliable and secure operation of production applications and supporting systems.

Artificial Intelligence & Automation: Identify practical opportunities to integrate AI into existing business applications and processes. Develop and implement AI-powered features using commercial or locally hosted large language models (LLMs).Integrate AI services and APIs with .NET and PHP applications. Explore applications involving conversational AI, speech-to-text, intelligent search, document processing, and workflow automation. Evaluate AI solutions for customer service, contact center operations, scheduling, reporting, and operational efficiency. Investigate AI-assisted infrastructure monitoring and troubleshooting capabilities. Evaluate new AI technologies for performance, security, reliability, and measurable business value. Prior professional AI experience is preferred but not required. Strong programming skills, technical curiosity, and the ability to learn and implement emerging technologies are more important.

Technical Ownership & Problem Solving: Take ownership of technical projects from initial concept through development, deployment, and ongoing support. Independently diagnose and resolve complex issues spanning applications, databases, and infrastructure. Work directly with business stakeholders to understand operational challenges and develop effective solutions. Recommend improvements to application architecture, system reliability, and development practices. Evaluate new technologies and determine their suitability for our business environment.

Required Qualifications: 8+ years of professional, hands-on software development and/or systems engineering experience, including substantial application development experience. Strong proficiency in C# and .NET Core / ASP.NET Core development. Practical experience developing, maintaining, or enhancing PHP applications. Experience designing and developing web applications, REST APIs, and database-driven business systems. Strong SQL skills and experience with PostgreSQL, MySQL, SQL Server, or comparable relational databases. Experience with Linux server administration and troubleshooting. Understanding of web application hosting, networking, security, and production environments. Experience with Git or comparable source control systems. Ability to independently design, develop, deploy, and troubleshoot production applications. Strong analytical skills and a demonstrated ability to solve complex technical problems.

Preferred Qualifications: Experience with Blazor Server or other modern .NET web frameworks. Experience with modern .NET application architecture and legacy application modernization. Strong PHP and LAMP stack development experience. Experience with Dapper or other .NET data access technologies. Experience with PostgreSQL and MySQL database administration and performance tuning. Experience with KVM, VMware, Hyper-V, or other virtualization platforms. Familiarity with Nginx, Apache, IIS, Docker, and reverse proxies. Experience with Linux scripting, infrastructure automation, and monitoring. Experience integrating third-party APIs, telephony systems, or contact center platforms. Familiarity with OpenAI, Anthropic, Ollama, or other cloud-based and locally hosted AI technologies. Experience building AI integrations, intelligent automation, or LLM-powered applications.

Salary: $160,000–$185,000 annually, depending on qualifications and experience.401(k) matching Health insurance Dental insurance Vision insurance Life insurance Paid time off Employee discount Referral program

Job Type: Full-time Work Location: In person — Jeffersonville, Indiana