Senior Mainframe COBOL Engineer – CRA Accounting

InstantServe LLC; South Carolina; On-site; USD 90,000 - 120,000; Full time

Job summary

InstantServe LLC is seeking an experienced Mainframe Developer to design, build, and enhance a Composite Reservoir Accounts system within a z/OS environment. You will extend legacy COBOL applications, implement new account structures, and ensure accurate balances, settlements, and reconciliations.

Responsibilities include analyzing master files, developing end-to-end account types, and extending nightly/month-end processing.

Qualifications

• Double-entry accounting, accruals, value dating, and reconciliation.
• Month-end financial processing.
• COBOL copybooks, call chains, and batch job streams.
• T SO/ISPF, GDGs, SORT, and JCL utilities.

Responsibilities

• Analyze existing account master, posting, and balance-maintenance programs to determine changes for Composite Reservoir Accounts.
• Design and develop the new account type end-to-end, including master file structures, account opening/closing, linkage, sweep processing, allocation logic, and closing balance calculations.
• Develop and modify Enterprise COBOL programs, JCL, and batch processing workflows.
• Extend nightly and month-end processing cycles to support the new functionality within batch windows.
• Implement audit trails, exception reporting, and reconciliation controls for the new structure.
• Collaborate with accounting stakeholders to establish financial controls and audit requirements.
• Prepare test data, unit tests, regression test cases, and parallel-run comparisons against production outputs.
• Investigate and resolve discrepancies to ensure financial accuracy.
• Support implementation, account conversion, production deployment, and early-life production support.

Skills

COBOL

JCL

Batch processing

TSO/ISPF

GDGs

SORT

z/OS

Accounting

REXX

Python

Java

IBM MQ

z/OS Connect

REST integration

Tools

IBM MQ

z/OS Connect

REST integration

Job description

InstantServe LLC is seeking an experienced Mainframe Developer to design, build, and enhance a Composite Reservoir Accounts system within a z/OS environment. You will extend legacy COBOL applications, implement new account structures, and ensure accurate balances, settlements, and reconciliations.

Responsibilities include analyzing master files, developing end-to-end account types, and extending nightly/month-end processing.