COBOL Developer & Code Expert at Mercor

COBOL Developer & Code Expert | $80–100/hr | Worldwide Remote

Mercor is seeking experienced COBOL developers to read, write, debug, and evaluate production-quality COBOL code. In this role, you will directly contribute to training and improving AI models on legacy software engineering workflows, with a focus on mainframe-style codebases. This is a flexible contractor opportunity ideal for seasoned COBOL engineers looking to apply their expertise in a cutting-edge AI context.

Responsibilities

• Read and interpret COBOL programs, copybooks, JCL, and related mainframe code.
• Write clean, correct COBOL code based on provided technical requirements.
• Debug COBOL logic and identify issues within existing programs.
• Clearly explain code behavior, business logic, and data flow to varied audiences.
• Review AI-generated COBOL solutions for correctness, completeness, and coding style.
• Create and evaluate test cases for COBOL programs.
• Provide high-quality, structured feedback to improve AI model performance on legacy code tasks.

Requirements

• Strong hands-on experience with COBOL development in real-world environments.
• Ability to independently read and write COBOL code to production standards.
• Familiarity with mainframe environments such as IBM z/OS (preferred).
• Experience with JCL, VSAM, DB2, CICS, or copybooks is a plus.
• Strong debugging and code review capabilities.
• Clear written communication skills in English.
• Background in banking, insurance, government, or enterprise legacy systems is advantageous.

Ideal Candidate

• Has worked on real-world COBOL systems beyond academic or training examples.
• Can explain legacy code clearly to both technical and non-technical stakeholders.
• Is comfortable evaluating code quality and reasoning through edge cases.
• Has experience maintaining or modernizing large-scale legacy codebases.

Why Join

• Contribute to cutting-edge AI systems focused on software engineering.
• Help AI models better understand and support legacy enterprise code.
• Engage in intellectually stimulating code evaluation and generation tasks.
• Enjoy a flexible, remote contractor arrangement suited to experienced engineers.