COBOL Mainframe Developer

Role overview

This is a remote contractor role for an experienced COBOL developer who can read, interpret, troubleshoot, and produce production-ready COBOL code. The work is centered on supporting tasks that train and assess AI models on legacy software engineering workflows, with a strong focus on mainframe-oriented codebases.

What you will do

• Analyze COBOL applications, copybooks, JCL, and related mainframe components.
• Develop accurate COBOL code aligned to technical specifications.
• Trace defects in COBOL logic and resolve problems in existing programs.
• Describe program flow, business rules, and data movement in a clear way.
• Evaluate AI-generated COBOL outputs for correctness, completeness, and coding quality.
• Build or assess test cases for COBOL routines.
• Deliver detailed feedback that helps improve AI performance on legacy development tasks.

What we are looking for

• Deep practical experience working with COBOL.
• Confidence reading and writing COBOL independently.
• Exposure to mainframe platforms such as IBM z/OS is preferred.
• Working knowledge of JCL, VSAM, DB2, CICS, or copybooks is an advantage.
• Strong troubleshooting ability and a solid eye for code review.
• Good written English communication skills.
• Background in banking, insurance, public sector, or large enterprise legacy systems is a plus.

Ideal background

• Real project experience with COBOL systems rather than only classroom or sample code.
• Ability to explain older code clearly to both technical and non-technical stakeholders.
• Comfort with assessing code quality and thinking through edge cases.
• Experience supporting, maintaining, or modernizing large legacy codebases.

Why this opportunity stands out

• Contribute to advanced AI systems built around software engineering.
• Help improve how models understand and support legacy enterprise code.
• Take on engaging code evaluation and code generation work.
• Flexible opportunity for seasoned COBOL engineers.

Additional information

This role is classified as a contractor position and is fully remote. All qualified applicants are considered without regard to legally protected characteristics, and reasonable accommodations can be provided on request.