Mainframe Developer

InterSources Inc; Columbia (SC); Remote; USD 100,000 - 180,000; Full time

Benefits offered by this job

Remote work

Job summary

InterSources Inc. in Columbia, SC is seeking an experienced COBOL mainframe developer for a 6-month remote assignment. You will analyze existing COBOL programs, design Composite Reservoir Accounts, and enhance batch processing to support nightly and month-end financial processing.

The role requires 5+ years in Enterprise COBOL on z/OS, NaturalOne, JCL, Adabas/VSAM, and strong debugging of legacy logic. Remote work with virtual interviews offered; candidate will maintain documentation and assist

Qualifications

• 5+ years of Enterprise COBOL development experience in a z/OS environment.
• 5+ years of NaturalOne experience.
• 5+ years of JCL development and production support.
• 3+ years in financial/accounting systems development or support, including double-entry posting, balance and accrual maintenance, value dating, reconciliation, and month-end closeouts in a regulated environment.
• 3+ years with Adabas and VSAM.
• 3+ years tracing undocumented legacy logic through copybooks, call chains, and job streams.
• Experience with cash management, account pooling, sweeps, or treasury applications.
• Experience with CA-7 scheduling and batch operations.
• Experience with REXX, Python, or Java.
• Experience integrating COBOL and Natural applications using z/OS Connect, IBM MQ, or REST services.
• Knowledge of CLIST scripting, batch performance tuning, and data migration.

Responsibilities

• Analyze existing COBOL programs, account master files, posting processes, and balance-maintenance logic to identify required enhancements.
• Design and develop Composite Reservoir Accounts, including account structures, participant linkage, cash sweeps, reverse sweeps, and interest allocation.
• Enhance COBOL batch programs, Natural applications, and JCL to support nightly and month-end financial processing.
• Implement accurate financial posting, balance calculations, accrual processing, reconciliation, and audit controls.
• Troubleshoot existing mainframe applications by tracing COBOL copybooks, program call chains, and JCL job streams.
• Develop test data and perform unit testing, regression testing, and parallel-run validation against existing production results.
• Investigate processing discrepancies and ensure financial accuracy without affecting existing account balances.
• Support production deployment, account conversion, batch execution, and post-implementation troubleshooting.
• Maintain technical documentation, data-flow diagrams, operational runbooks, and change-control records.

Skills

COBOL / z/OS

NaturalOne

JCL

Financial systems

Adabas / VSAM

Legacy code analysis

Cash management

CA-7 scheduling

REXX / Python / Java

z/OS Connect / MQ / REST

CLIST scripting

Job description

Location: Columbia, SC 100% Remote

Duration: 6 Months (Possible Extension)

Interview: 1–2 Rounds of Virtual Interviews

Required Skills

• 5+ years of Enterprise COBOL development experience in a z/OS environment.
• 5+ years of experience with NaturalOne.
• 5+ years of JCL development and production support experience.
• 3+ years of financial/accounting systems development or support, including double-entry posting, balance/accrual maintenance, value dating, reconciliation, and month-end closeouts in a regulated environment.
• 3+ years of experience working with Adabas and VSAM.
• 3+ years of experience tracing undocumented legacy logic through copybooks, call chains, and job streams.

Preferred Skills

• Experience with cash management, account pooling, sweeps, or treasury applications.
• Experience with CA-7 scheduling and batch operations.
• Experience with REXX, Python, or Java.
• Experience integrating COBOL and Natural applications using z/OS Connect, IBM MQ, or REST services.
• Knowledge of CLIST scripting, batch performance tuning, and data migration.

Key Responsibilities

• Analyze existing COBOL programs, account master files, posting processes, and balance-maintenance logic to identify required enhancements.
• Design and develop Composite Reservoir Accounts, including account structures, participant linkage, cash sweeps, reverse sweeps, and interest allocation.
• Enhance COBOL batch programs, Natural applications, and JCL to support nightly and month-end financial processing.
• Implement accurate financial posting, balance calculations, accrual processing, reconciliation, and audit controls.
• Troubleshoot existing mainframe applications by tracing COBOL copybooks, program call chains, and JCL job streams.
• Develop test data and perform unit testing, regression testing, and parallel-run validation against existing production results.
• Investigate processing discrepancies and ensure financial accuracy without affecting existing account balances.
• Support production deployment, account conversion, batch execution, and post-implementation troubleshooting.
• Maintain technical documentation, data-flow diagrams, operational runbooks, and change-control records.

Key Technical Expectations

Candidates should be prepared to demonstrate hands‑on experience with:

• COBOL / z/OS: Enterprise COBOL batch and online processing, legacy application enhancements, and production troubleshooting.
• NaturalOne / Natural / Adabas: Natural programs, subprograms, maps, DDMs, descriptors, superdescriptors, development, debugging, and deployment.
• JCL / Mainframe Operations: JCL, PROCs, GDGs, SORT utilities, restart/rerun procedures, and TSO/ISPF.
• Financial Systems: Double-entry accounting, accruals, value dating, account balances, reconciliation, and month-end close.
• Legacy System Analysis: Reverse-engineering undocumented logic and assessing downstream impacts of production changes.