Senior Mainframe Developer (zOS)

Job location: Columbus, OH or Nashville, TN (both locations would be for on site work)

The Senior Mainframe Developer will support a critical legacy platform (MACSS) within a large-scale modernization initiative. This role is key to stabilizing and enhancing the core mainframe applications while enabling integration with modern API and event-driven platforms.

You will play a pivotal role in supporting production systems, delivering enhancements, and ensuring seamless integration with z/OS Connect-based services as part of a broader digital transformation program.

Key Responsibilities:

• Own and support a core mainframe application (MACSS) across production, enhancements, and project initiatives
  


• Develop and maintain applications using COBOL, JCL, DB2, and CICS
  


• Troubleshoot and resolve production issues across batch and online systems
  


• Collaborate with API and platform teams to enable integration via z/OS Connect services
  


• Support data flows and service exposure to downstream platforms (APIM, Kafka, etc.)
  


• Participate in system design discussions to support modernization and integration efforts
  


• Ensure performance, reliability, and scalability of legacy systems
  

This position is critical in enabling the organization’s transition to a modern, API-driven architecture by ensuring the stability and scalability of its core legacy systems.

Requirements

• 8+ years of hands-on mainframe development experience
  


• ​Strong expertise in:
  

• COBOL
  


• JCL
  


• DB2
  


• CICS
  




• Proven experience supporting production systems and critical applications
  


• Experience working in large enterprise environments (preferably utilities, banking, or insurance)
  


• Strong debugging and problem-solving skills in complex legacy environments
  

Preferred Qualifications:

• Utilities industry experience.
  


• Experience with IBM z/OS Connect
  


• Exposure to API enablement of mainframe systems
  


• Familiarity with event-driven architectures (Kafka or similar)
  


• Experience supporting systems undergoing modernization or digital transformation.