We are looking for an experienced Legacy Mainframe SME / Modernization Specialist to support a large-scale application modernization initiative within a regulated financial services environment. The role will focus primarily on reverse-engineering legacy mainframe applications, extracting business rules, documenting legacy behavior, and providing subject-matter expertise to the modernization team.
The ideal candidate has deep hands-on experience with COBOL, CICS, DB2, JCL, VSAM, and z/OS, combined with strong analytical and documentation skills. The candidate must be comfortable working with undocumented or outdated legacy systems and translating complex technical logic into clear, evidence-based specifications for teams with limited mainframe experience.
Key Responsibilities
1. Legacy Analysis & Business Rule Extraction
- Reverse-engineer COBOL, CICS, and batch programs to determine functional intent, business rules, calculations, and processing logic where documentation is unavailable or outdated.
- Build and maintain a Business Rule Inventory (BRI), documenting extracted rules with traceability to the specific program, paragraph, and line of code.
- Identify and distinguish active business logic from dead code, workarounds, obsolete branches, and legacy defects that should not be carried forward into the modernized solution.
- Analyze and document legacy data structures, including copybooks, COMP-3 packed decimal fields, OCCURS/REDEFINES structures, and EBCDIC encoding, including field-level definitions, valid values, and known data quality issues.
- Create dependency maps covering programs, copybooks, files, job streams, and DB2 objects.
- Identify ambiguities, inconsistencies, and undocumented dependencies and provide evidence-based recommendations.
2. Subject-Matter Support to the Modernization Team
- Serve as the primary point of contact for legacy behavior and application logic questions raised by the modernization team.
- Provide evidence-based responses by referencing the specific program, paragraph, data condition, or processing flow supporting each conclusion.
- Trace ambiguous or conflicting logic back to source code and escalate potentially unintended legacy behavior to appropriate business stakeholders.
- Maintain a searchable Q&A and decision log to ensure recurring questions and decisions are documented and reusable.
- Facilitate working sessions and walkthroughs to explain complex legacy application flows to modernization teams.
- Translate legacy technical logic into clear specifications and explanations that can be understood by engineers without mainframe backgrounds.
3. Baseline & Validation Support
- Produce legacy baseline outputs and representative test datasets for comparison against the modernized system.
- Develop baseline scenarios covering normal, boundary, exception, and error conditions.
- Investigate discrepancies between legacy and modernized applications and determine whether the legacy behavior is functioning as designed.
- Support parallel-run activities, including legacy job execution, data extraction, result preparation, and comparison.
- Provide analysis and evidence to support validation and reconciliation activities.
4. Legacy Maintenance During Transition
- Maintain and enhance in-scope legacy applications while modernization activities are ongoing.
- Follow established change management, release, and control processes for all legacy application changes.
- Provide production support for components affected by modernization activities.
- Participate in an on-call rotation during critical production and migration windows, as required.
- Support cutover rehearsals, fallback activities, and post-migration reconciliation from the legacy application perspective.
5. Documentation & Delivery Standards
- Comply with account requirements related to change management, audit, documentation, and traceability.
- Ensure all business rules, decisions, assumptions, deviations, and analysis conclusions are properly evidenced and traceable.
- Produce high-quality technical analysis, specifications, dependency maps, knowledge-transfer materials, and other documentation.
- Ensure documentation and knowledge-transfer artifacts remain accurate, searchable, and usable by the modernization team after the engagement.
- Work effectively within a ticket-based and traceable delivery environment using tools such as Jira, Confluence, or equivalent platforms.
Required Qualifications
- Bachelor's degree in Computer Science, Information Technology, Engineering, or a related field; equivalent demonstrable experience may be considered.
- 10+ years of hands-on mainframe application development experience.
- Proven experience independently analyzing undocumented or poorly documented legacy applications.
- Strong ability to reconstruct business rules and technical logic from source code and defend conclusions using source-level evidence.
Mainframe Technical Skills – Must Have
- COBOL – production-level experience, including complex copybook structures, REDEFINES, OCCURS DEPENDING ON, and packed decimal arithmetic.
- CICS – online transaction programming, pseudo-conversational design, COMMAREA, and channel/container patterns.
- DB2 for z/OS – embedded SQL, cursor processing, unit-of-work concepts, and commit scope.
- JCL, VSAM, and z/OS utilities – ability to understand and reconstruct end-to-end batch processing cycles.
- Strong understanding of mainframe application architecture, data flows, batch processing, and online transaction processing.
Analysis & Communication Skills – Must Have
- Demonstrated ability to translate complex legacy technical logic into clear, structured written specifications for engineers without mainframe backgrounds.
- Excellent written and verbal English communication skills.
- Strong analytical and problem-solving capabilities.
- Highly disciplined documentation practices with strong attention to detail and traceability.
- Ability to manage a high volume of technical queries while maintaining responsiveness, accuracy, and reliability.
- Experience working in ticket-based delivery environments such as Jira, Confluence, or equivalent tools.
Preferred Qualifications
- Experience in insurance, life and annuity, banking, or financial services, particularly in policy administration, underwriting, claims, billing, valuation, or actuarial data flows.
- Previous experience as a Legacy SME, Mainframe SME, Application SME, or Knowledge Transfer Specialist supporting distributed or offshore development teams.
- General understanding of modern application concepts such as relational data modeling, APIs, and object-oriented architecture.
- Exposure to automated legacy transformation and modernization tools such as AWS Blu Age, Micro Focus, Heirloom, TSRI, EvolveWare, or similar platforms.
- Knowledge of IMS DB/DC, IBM MQ Series, or z/OS Connect.
- Experience using AI-assisted development and code comprehension tools such as Claude Code, Cursor, or GitHub Copilot.
- Experience with REXX or Python for analysis, scripting, or automation.
- Experience with GnuCOBOL or containerized COBOL environments for offline code analysis and testing.
- Agile/Scrum delivery experience.
- Candidates must be open to working a mid/night shift to support collaboration with global teams.
