Mainframe Developer – Contract - Columbia, SC

Mainframe Developer – Composite Reservoir Accounts (COBOL & NaturalOne)
Location: Remote

Interview Process: 1-2 Rounds of Virtual Interviews
Duration: 12 Months
Employment Type: Contract
Experience Required: 06+ Years

Candidate location: No SC residency required. Candidate must reside in lower 48 states (Continental US) and comfortable working EST time zone hours.

Project Scope:

The Mainframe Developer will enhance an existing z/OS mainframe accounting platform by developing composite reservoir accounts (CRAs). These pooled accounts consolidate balances from multiple subsidiary accounts into a single reservoir account and distribute funds back according to defined sweep and allocation rules.

This role involves extending existing legacy mainframe functionality while maintaining the accuracy and integrity of current account balances and accounting operations. The developer will analyze existing COBOL programs, identify required changes, and implement the new account type across posting, settlement, accrual, reporting, and reconciliation processes.

Strong attention to detail, financial accounting knowledge, and the ability to work with complex, lightly documented production code are essential.

Key Responsibilities:

• Analyze existing account master, posting, and balance-maintenance programs to identify where composite reservoir accounts must be incorporated.
  
• Document existing system functionality and the impact of proposed changes.
  
• Design and develop the new account type, including:
  
• Master file and table structures.
  
• Account opening and closing.
  
• Participant account linkage.
  
• Sweep and reverse-sweep processing.
  
• Allocation and interest apportionment.
  
• Closing balance calculations.
  
• Modify batch COBOL programs and JCL to support the new functionality.
  
• Extend nightly and month-end processing cycles while maintaining agreed batch-window limits.
  
• Enhance audit trails, exception reporting, and reconciliation controls.
  
• Coordinate with accounting stakeholders to establish audit and evidence requirements.
  
• Prepare test data, unit tests, and regression test packs.
  
• Perform parallel-run comparisons against existing production outputs and investigate discrepancies.
  
• Support implementation, conversion of in-scope existing accounts, and early production cycles.
  
• Provide on-call support during initial processing cycles.
  
• Maintain program documentation, data-flow notes, and operational runbooks.
  

Required Skills & Experience:

• 5+ years of Enterprise COBOL development experience in a z/OS environment, including substantial production experience with batch and online programs.
  
• 3+ years of composite reservoir account experience.
  
• 5+ years of experience with NaturalOne.
  
• 3+ years of JCL development and production support experience.
  
• 3+ years of experience developing or supporting financial/accounting systems, including:
  
• Double-entry posting.
  
• Balance and accrual maintenance.
  
• Value dating.
  
• Reconciliation.
  
• Month-end closeouts in a regulated environment.
  
• 3+ years of experience working with Adabas and VSAM.
  
• 3+ years of experience tracing undocumented system logic through copybooks, call chains, and job streams.
  

Technical Skills – Required

• Enterprise COBOL: Strong production experience with Enterprise COBOL on z/OS, including modifying large existing programs and understanding code written by other developers.
  
• NaturalOne: Hands-on experience with the Eclipse-based Software AG development environment, including developing, debugging, and deploying Natural applications in local and remote z/OS projects.
  
• Natural and Adabas: Experience with Natural programs, subprograms, maps, DDMs, descriptors, superdescriptors, and Adabas file design and performance.
  
• z/OS and JCL: Ability to write and debug JCL, procedures (PROCs), GDGs, utilities, SORT operations, and restart/rerun handling. TSO/ISPF proficiency is expected.
  
• Mainframe Data Stores: Experience with VSAM file design and access, as well as Adabas for z/OS.
  
• Financial Accounting: Understanding of double-entry posting, balance and accrual maintenance, value dating, reconciliation, and month-end closing in regulated environments.
  
• Legacy System Analysis: Ability to trace undocumented logic through copybooks, call chains, and job streams and clearly explain the impact of proposed changes.
  

Preferred Skills:

• Experience with cash management, account pooling, sweep processing, or treasury applications.
  
• Experience with CA-7 scheduling and batch operations.
  
• Experience with REXX, Python, or Java.
  
• Experience integrating COBOL and Natural applications.
  
• Exposure to z/OS Connect, IBM MQ, or REST services.
  
• Experience with CA-7 batch-window analysis and performance tuning.
  
• Experience using REXX or CLIST for tooling and Java or Python for data comparison and migration activities.
  
• Knowledge of notional and physical pooling, cash concentration, sweeps, and intercompany allocation.
  

Education:
High School Diploma or equivalent.