Software Systems Engineer

Sr. Software Systems Engineer (C#/.NET Developer) Marathon is searching for a motivated, career and customer-oriented Sr. Software Engineer (C#/.NET Developer) who will work across EDI transaction processing, backend API development, and cloud native systems on AWS. This is a hands-on engineering role with direct impact on how VA healthcare data flows through our platform. This is a 100% Remote role. JOB DESCRIPTION * Design, build, and maintain C#/.NET/AWS backend services handling high-volume healthcare EDI transactions (837, 835, etc.) * Parse, validate, and transform X12 EDI documents * Debug complex transaction-level issues across payers, clearinghouses, and trading partners * Write, optimize, and troubleshoot SQL stored procedures including performance tuning, query analysis, and complex data transformations * Work with XML object store data: query, parse, and manipulate structured XML within MSSQL * Write clean, testable, well-documented code and participate actively in code review * Contribute to shared platform libraries and services used across multiple product initiatives * Performs technical planning, high level and detailed requirements definition, test planning and execution with team members and stakeholders on a daily basis * Serve as an active member of the software development team participating in daily stand-ups * Deploy, support and ensure the performance, quality, and responsiveness of application * Provide development support, as needed, for solutions deployed to production * Implement long term solutions and building blocks within the agile framework for improved reusability * Apply and promote best software engineering practices * Use Integrated Development Environment (IDE) tools to include Visual Studio and Git Education * Bachelor's or master's degree in computer science, electronics engineering or other engineering or technical discipline is required. Experience * Minimum of 8 years of experience in software development using C#/.NET technologies * Proven track record of working on complex software projects and leading development initiatives * Experience with designing, developing, and deploying enterprise-level applications Requirements * Strong proficiency in C#/.NET ecosystem * Proficiency in developing back-end applications using design and integration patterns * Hands-on AWS experience (serverless, messaging, storage, databases) preferred * Strong SQL skills: writing and optimizing stored procedures, troubleshooting execution plans, performance tuning in MSSQL * Proficient with Git and GitHub * Experience with MSSQL or similar relational databases * Proficiency in database design and development, including working with SQL Server and Entity Framework. * Familiarity with cloud platforms (e.g., Microsoft Azure, AWS) and services. * Understanding of continuous integration/continuous deployment (CI/CD) practices and tools (e.g., AWS CodePipeline, CodeBuild, CodeDeploy). * Knowledge of unit testing frameworks and tools (e.g., NUnit, xUnit, MSTest). - Proficiency in using development tools like Visual Studio and Visual Studio Code. * Excellent problem-solving and analytical skills. * Strong communication and interpersonal abilities. * Ability to work independently and as part of a large team. * Attention to detail and commitment to producing high-quality software. * Ability to prioritize tasks and manage time effectively using JIRA. * Experience with agile development methodologies (e.g., Scrum, Kanban). * Familiarity with DevOps practices and infrastructure as code (IaC). * Ability to conduct code reviews and provide constructive feedback. * Experience with performance tuning and optimization of applications. * Knowledge of microservices and event-driven architecture and containerization technologies (e.g., Docker, ECS, EKS) is a plus. * Experience with healthcare payer/PBM systems, clearinghouses, or pharmacy operations is a plus Clearance Requirement: * US Citizenship with the ability to obtain and maintain a Public Trust clearance