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Senior Mainframe COBOL Developer -W2 Only

MSys Inc.

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At a glance

Compensation
No compensation found
Location
Remote · US
Schedule
Contract
Work Authorization
Not specified

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Job overview

The Senior Mainframe COBOL Developer will extend a production legacy accounting platform to support composite reservoir accounts. The work includes analyzing existing COBOL programs, implementing account and transaction processing, modifying batch cycles, and adding audit and reconciliation controls. The developer will create test packs, support conversion and early production runs, and document the changes. The posting requires substantial mainframe and financial-systems experience; cash-management and related skills are preferred.

Skills & qualifications

RequiredNice to have

Skills

Enterprise COBOL, requiredNaturalOne, requiredJCL Development, requiredFinancial Systems Development, requiredDouble-Entry Posting, requiredBalance and Accrual Maintenance, requiredValue Dating, requiredReconciliation, requiredMonth-End Close, requiredAdabas, requiredVSAM, requiredLegacy Logic Tracing, requiredNatural, requiredDDM Design, requiredAdabas File Design, requiredZ/OS, requiredTSO/ISPF, requiredBatch Operations, requiredOnline Processing, requiredCash Management, nice to haveAccount Pooling, nice to haveSweep Processing, nice to haveTreasury Applications, nice to haveCA-7, nice to haveREXX, nice to havePython, nice to haveJava, nice to haveCOBOL-Natural Integration, nice to haveZ/OS Connect, nice to haveIBM MQ, nice to haveREST Services, nice to haveCLIST, nice to haveCash Concentration, nice to haveIntercompany Allocation, nice to haveProduction Implementation, nice to haveWritten Communication, nice to have

Qualifications

5+ Years Enterprise COBOL Experience, required5+ Years NaturalOne Experience, required3+ Years JCL Experience, required3+ Years Financial Systems Experience, required3+ Years Adabas and VSAM Experience, required3+ Years Legacy Logic Tracing Experience, requiredComputer Science Degree or Equivalent Experience, nice to have

Full job description

*** Mode of Interview :- WebCam interview *** Long term *** Remote *** W2 Only***

Description:

About The Role:-

We are adding new composite reservoir accounts to our existing mainframe accounting platform: a pooled account structure in which balances from multiple subsidiary accounts are concentrated into, and drawn back from, a single reservoir account under defined sweep and allocation rules. This is additional function inside a legacy system. You will be reading a large body of COBOL that has been in production for an extended period, much of it lightly documented, and extending it so that the new account type posts, settles, accrues, reports, and reconciles exactly as the existing types do. Correctness and traceability of every cent matter more than speed of delivery.

What You Will Do:-

  • Analyze the current account master, posting, and balance-maintenance programs to establish where composite reservoir accounts must be recognized, and document what you find.

  • Design and code the new account type end to end: master file and table structures, account opening and closing, participant linkage, sweep and reverse-sweep logic, allocation and interest apportionment, and closing balance derivation.

  • Modify batch COBOL programs and JCL and extend the nightly and month-end cycles to include the new processing without lengthening the batch window beyond agreed limits.

  • Add new CRAs to the audit trail, exception reporting, and reconciliation controls the new function requires, working with accounting stakeholders on what must be evidenced.

  • Produce test data, unit and regression test packs, and parallel-run comparisons against current production output; investigate every difference until it is explained.

  • Support implementation, conversion of any in-scope existing accounts, and early-life production runs, including on-call cover during the first cycles.

  • Leave behind program documentation, data-flow notes, and runbook updates that the support team can work from.

Required Skills:-

  • 5+ years of Enterprise COBOL development experience in a z/OS environment

  • 5+ Years of Experience with NaturalOne

  • 3+ years of JCL development and production support experience

  • 3+ years of experience with 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 with tracing undocumented logic through copybooks, call chains, and job streams

These are the skills we expect to see evidence of in the first conversation.

  • COBOL — substantial production experience in Enterprise COBOL on z/OS, both batch and online; comfortable extending large existing programs and reading code you did not write.

  • NaturalOne — the Eclipse-based Software AG development environment; developing, debugging, and deploying Natural applications from it, including local development and remote z/OS projects.

  • Natural and Adabas — Natural programs, subprograms, and maps; DDMs, descriptors and superdescriptors, and Adabas file design and performance behavior.

  • z/OS and JCL — writing and debugging JCL, procs, GDGs, utilities, SORT, and restart/rerun handling; fluent in TSO/ISPF.

  • Mainframe data stores — VSAM file design and access, and Adabas for z/OS.

  • Financial accounting logic — double-entry posting, balance and accrual maintenance, value dating, reconciliation, and month-end close in a regulated environment.

  • Analysis of legacy systems — tracing undocumented logic through copybooks, call chains, and job streams, and stating clearly what a change will and will not affect.

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

Not required to apply. Each of these will shorten your ramp-up, and we will support you in learning the ones you do not have.

  • Mixed-estate integration — calling between COBOL and Natural, and exposing mainframe function through z/OS Connect, IBM MQ, or REST services.

  • Scheduling and operations — CA-7 batch window analysis and performance tuning.

  • Scripting and adjacent languages — REXX or CLIST for tooling, plus Java or Python for data comparison and migration work.

  • Cash management domain — notional and physical pooling, cash concentration, sweeps, and intercompany allocation.

Additional Skills:-

  • Track record of taking a specification from analysis through production implementation with limited supervision.

  • Clear written communication: you can explain a change to an auditor, a business analyst, and another developer, and adjust the explanation for each.

  • Degree in computer science or a related field, or equivalent practical experience.

How this job compares

Set against the 38,785 open Software Engineer jobs on Olive Jobs, counted November 14, 2026.

Pay
  • This postingNot listed
  • US median$132–214K/yr31,373 salary ranges
  • US median$50–65/hr991 hourly ranges
Openings
Olive Jobs lists 38,785 open Software Engineer jobs across the US. 8% of them nationwide are listed as remote or flexible.
Hiring the most across the US
Experience
This posting asks for at least 5 years of experience; Software Engineer postings that state a minimum ask for 5 years at the median (32,072 postings).
Education
12,065 of the 38,785 open Software Engineer jobs (31%) ask for a bachelor's degree or higher.

Pay, requirements and demand for Software Engineer jobs

Counted across the open, public US postings on Olive Jobs on November 14, 2026. Figures based on too few postings are left out.

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