.Net Developer, Intermediate

Advanced Systems Design is seeking a .Net Developer, Intermediate for our client located in Montgomery, AL.

This position is onsite in Montgomery, AL, and requires in-person availability starting day 1.

We are seeking a Mid-Level Microsoft .Net Developer with Mainframe development experience to support and enhance mission-critical enterprise applications in a complex hybrid environment that includes both legacy mainframe systems and modern Microsoft technologies. This role will be responsible for development, maintenance, modernization, system integrations, reporting solutions, and production support activities.

The ideal candidate will possess strong mainframe and Microsoft .Net development experience, solid database skills, and the ability to bridge legacy systems with modern application architectures. This individual will work closely with business analysts, project managers, database administrators, and cross-functional development teams to deliver scalable, secure, and maintainable solutions.

• Analyze, interpret, and decode legacy Easytrieve enterprise applications running on IBM mainframe platforms.
• Analyze business requirements and translate them into technical specifications and application solutions.
• Design, develop, test, and deploy application enhancements and defect fixes.
• Support batch processing, data transformation, and enterprise integration workflows.
• Develop and maintain reports, extracts, and data distribution processes.
• Create and support ETL solutions using SQL Server Integration Services (SSIS).
• Design, develop, and maintain reporting solutions using SQL Server Reporting Services (SSRS).
• Develop and maintain applications and supporting utilities using .NET technologies.
• Write, optimize, and troubleshoot complex SQL queries, stored procedures, views, and database objects.
• Monitor and resolve production support issues while ensuring system stability and data integrity.
• Participate in application modernization and legacy migration initiatives.
• Collaborate with business users to troubleshoot issues and identify process improvements.
• Create and maintain technical documentation, application specifications, and support procedures.
• Participate in code reviews and ensure compliance with organizational coding standards.
• Support testing efforts including unit, integration, regression, architecture, and user acceptance testing.

• Significant familiarity with the CMS Advise (835) and CMS 837 Health Care Claim file elements and standards.
• 3–7 years of professional software development experience.
• 3+ years of experience in IBM Mainframe development environments.
• Experience supporting large-scale enterprise applications.
• Strong analytical, troubleshooting, and problem-solving skills.
• Excellent written and verbal communication skills.
• Strong problem-solving and root-cause analysis abilities.
• Ability to work independently with minimal supervision.
• Effective collaboration across technical and business teams.
• Strong organizational and time management skills.
• Ability to manage multiple priorities and deadlines.
• Commitment to quality, accuracy, and continuous improvement.
• Strong customer service mindset and support orientation.
• Mainframe Technologies
  • JCL
  • CICS
  • ROSCOE or TSO
  • Easytrieve/Easy Plus
  • Batch Processing
• Microsoft Technologies
  • .NET Framework / .NET Core
  • C#
  • Entity Framework Core
• Database & Reporting
  • SQL Server
  • T-SQL
  • SSRS (SQL Server Reporting Services)
  • SSIS (SQL Server Integration Services)
  • Stored Procedures
  • Database Performance Tuning
• Development Tools
  • Visual Studio
  • Git
  • Azure Dev Ops Server
  • SQL Server Management Studio (SSMS)
  • Markdown File for Documentation
  • EDI Fabric SDK

• Experience with application modernization and migration of legacy systems.
• Experience using off-the-shelf technologies to manipulate data and report upon CMS data files (835 & 837)
• Experience parsing, generating, and troubleshooting ANSI ASC X12 HIPAA transaction sets, specifically 837 (claims submission) and 835 (Electronic Remittance Advice / ERA)
• Experience working with Alabama Medicaid electronic data specifications, companion guides, and proprietary state formats.
• Experience integrating mainframe applications…