Mainframe Developer

Seven Seven; Pasig; On-site; PHP 1,200,000 - 1,900,000; Full time

Job summary

Seven Seven is seeking an experienced Legacy Mainframe SME / Modernization Specialist to support a large-scale application modernization in a regulated financial services environment. The role focuses on reverse‑engineering legacy mainframe systems, extracting business rules, and documenting legacy behavior to guide modernization efforts.

The ideal candidate has deep hands-on COBOL, CICS, DB2, JCL, VSAM, and z/OS experience, with strong analytical and documentation skills.

Qualifications

• Bachelor’s degree or equivalent experience in CS/IT/Engineering.
• 10+ years of hands-on mainframe development experience.
• Proven ability to analyze undocumented legacy applications and extract business rules.

Responsibilities

• Reverse‑engineer COBOL, CICS, and batch programs to determine functional intent and processing logic.
• Build and maintain a Business Rule Inventory with traceability to program and line of code.
• Create dependency maps for programs, copybooks, files, job streams, and DB2 objects.
• Serve as primary SME for legacy behavior and application logic questions of modernization teams.
• Document legacy data structures (copybooks, packed decimals, OCCURS/REDEFINES, EBCDIC) with field definitions and values.
• Produce baseline outputs and test datasets for validation and reconciliation during modernization.

Skills

COBOL

CICS

DB2 for z/OS

JCL

VSAM

z/OS

Documentation

English communication

Education

Bachelor's degree in Computer Science/IT/Engineering

Tools

Jira

Confluence

Job description

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 The candidate must be comfortable working with undocumented or outdated legacy systems and translating complex technical logic into clear, evidence‑based specifications for teams with limited mainframe experience.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

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.

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 elevate 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.

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.
• 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.

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.