Mainframe Developer (COBOL, z/OS)

SOWJANYA NALLAGATLA

MAINFRAME DEVELOPER COBOL JCL DB2 CICS VSAM IBM z/OS

+1-404-***-**** *******************@*****.*** linkedin.com/in/nasowjany

Open to Relocation

PROFESSIONAL SUMMARY

Mainframe Developer with approximately 5 years of experience developing and supporting banking, payments, and healthcare applications on IBM z/OS.

Develop and maintain COBOL, JCL, DB2, CICS, and VSAM solutions for high-volume batch processing and online transaction processing.

Translate business requirements into impact assessments, technical designs, development estimates, application enhancements, and test scenarios.

Build JCL job streams and reusable PROCs with job dependencies, condition codes, and restart/recovery procedures; support Control-M batch schedules.

Write DB2 SQL, joins, cursors, and stored procedures; use SPUFI, QMF, and EXPLAIN analysis for data validation and query optimization.

Diagnose production abends and application failures using Xpediter, Abend-AID, IBM Fault Analyzer, SDSF, and CEEDUMP; document root causes and permanent fixes.

Support CICS programs and BMS maps, IBM MQ integration, and REST API enablement through IBM z/OS Connect EE for distributed application consumers.

Bring domain experience in core banking, institutional payments, claims adjudication, member eligibility, benefits, EDI 835/837, and HIPAA 5010 workflows.

Deliver changes through unit testing, regression testing, SIT, UAT, controlled source promotion, and post-release validation using Endevor and ChangeMan.

Apply REXX/CLIST automation and participate in platform migration, disaster-recovery testing, Agile/Scrum delivery, peer reviews, and technical documentation.

Use GitHub Copilot as an assistive tool for legacy-code analysis, debugging preparation, and documentation, with human review and project security controls.

Partner with Product, Business, Architecture, Security, and Operations stakeholders to align application changes with business objectives, delivery priorities, and release timelines.

Apply Agile/DevOps, CI/CD, automated testing, and observability practices to improve the reliability, performance, availability, and security of enterprise-scale, highly available systems.

Support modernization of mainframe workloads toward cloud-native, API-driven, microservices, and event-driven architectures using z/OS Connect EE, IBM MQ, and AWS/Azure.

Communicate technical designs, risks, dependencies, and delivery status clearly to business and technical stakeholders; track work in Jira, HP ALM, and equivalent lifecycle management tools.

TECHNICAL SKILLS

Development: COBOL, COBOL II, JCL, SQL, REXX, CLIST; CICS, BMS maps; IBM z/OS, TSO/ISPF, SDSF

Data and integration: DB2, VSAM KSDS/ESDS, SPUFI, QMF, EXPLAIN, IBM MQ, IBM z/OS Connect EE, REST/SOAP integration

Batch and utilities: Control-M, DFSORT/SYNCSORT, IDCAMS, ICETOOL, IEBGENER, IEBCOPY, File-AID, File Manager, Connect:Direct

Debugging and delivery: Xpediter, Abend-AID, IBM Fault Analyzer, CEEDUMP, Endevor, ChangeMan, Git, Jira, Confluence, HP ALM

Additional toolkit: PL/I; IMS DB/DC, DL/I; CA-7, TWS, ESP; IDz, IBM zOpen Editor; IBM Debug Tool, INTERTEST, Topaz

Exposure and concepts: Assembler basics; Jenkins/mainframe DevOps; AWS/Azure fundamentals; GitHub Copilot, ChatGPT

Engineering practices: Agile/Scrum, DevOps, CI/CD, Jenkins, SDLC methodologies, automated testing, code reviews, observability and monitoring, system reliability, performance optimization, security principles, engineering productivity

Architecture and platforms: Cloud-native architectures, APIs (REST), microservices, event-driven systems (IBM MQ), distributed and highly available systems, platform modernization, HLD/LLD technical design

Delivery and collaboration: Application lifecycle management (Jira, HP ALM, Confluence, Rally-equivalent tools), cross-functional stakeholder communication, risk and dependency management, prioritization, operational metrics, continuous improvement, technical documentation

PROFESSIONAL EXPERIENCE

Goldman Sachs New York, NY (Remote)

Senior Mainframe Developer — Core Banking and Payments January 2025 – Present

Develop and enhance COBOL/CICS/DB2 applications supporting core banking and institutional payments across batch and online workflows.

Analyze requirements and program dependencies, prepare low-level designs, and estimate effort for COBOL, JCL, and DB2 changes.

Goldman Sachs Senior Mainframe Developer (continued)

Optimize COBOL batch programs using DB2, VSAM, and DFSORT/SYNCSORT for extraction, reconciliation, and regulatory reporting.

Maintain JCL job streams, reusable PROCs, and Control-M schedules; resolve dependencies, condition-code issues, and restart/recovery requirements.

Develop CICS programs and BMS maps; troubleshoot transaction failures and tune application paths to support response-time and availability objectives.

Write DB2 joins, cursors, and stored procedures; use SPUFI/QMF and EXPLAIN to investigate inefficient access paths and tune SQL.

Investigate COBOL, JCL, CICS, and DB2 incidents using Abend-AID, Fault Analyzer, Xpediter, SDSF, and CEEDUMP; resolve abends and document corrective actions.

Expose CICS business services as REST APIs through IBM z/OS Connect EE and validate integration with Java/microservices applications and IBM MQ message flows.

Coordinate unit, regression, SIT, and UAT testing; review code, promote changes through Endevor/Git processes, and support post-release verification.

Support disaster-recovery exercises, application recovery steps, and VSAM backup/restore validation; maintain implementation plans and operational runbooks.

Use REXX/CLIST and z/OS utilities for repetitive support tasks; apply GitHub Copilot assistance to code analysis, debugging preparation, and documentation with review controls.

Partner with Product, Architecture, Security, and Operations teams to clarify scope, manage dependencies and delivery risks, and prioritize work across concurrent releases.

Contribute to reliability and continuous-improvement efforts by analyzing recurring incidents and recommending permanent fixes, monitoring, and automation across batch and online workloads.

PROFESSIONAL EXPERIENCE CONTINUED

CareSource Dayton, OH (Offshore delivery from India)

Mainframe Developer — Healthcare Claims and Benefits June 2020 – July 2023

Developed COBOL/JCL/DB2 applications for claims adjudication, member eligibility, benefits processing, and Explanation of Benefits generation.

Analyzed requirements and existing program flows, assessed impacts, and implemented business-rule changes across batch and CICS applications.

Maintained claims intake and validation batch cycles; monitored JCL jobs, diagnosed failures, and executed restart/recovery procedures.

Processed EDI 835/837 healthcare transactions and supported HIPAA 5010 validation for claims and payment files.

Built CICS/BMS functions for member lookup, claims-status inquiry, and provider authorization tracking; maintained DB2 SQL, stored procedures, and triggers.

Maintained VSAM KSDS/ESDS datasets with IDCAMS and File-AID; validated data and supported IBM MQ exchange with downstream Java applications.

Diagnosed COBOL abends and DB2 SQL errors using Xpediter and Fault Analyzer; automated file-management and support tasks with REXX/CLIST.

Supported OS/390-to-z/OS 2.4 migration activities, runtime compatibility remediation, and revalidation of COBOL programs, JCL streams, and batch interfaces.

Prepared unit-test data, executed SIT, and supported UAT/regression testing; tracked defects in HP ALM/Jira and promoted changes through ChangeMan.

Collaborated with business, QA, and operations teams on production fixes and release readiness; documented HLD/LLD designs and support handovers.

Communicated delivery status, risks, and dependencies to business and operations stakeholders in Agile/Scrum ceremonies; followed SDLC, security, and HIPAA compliance controls.

EDUCATION AND CERTIFICATIONS

Master of Science in Information Studies Trine University, United States 2023 – December 2024

IBM Certified Application Developer — COBOL for z/OS

IBM z/OS 2.x Associate — Mainframe Practitioner Certification

Professional development: Microsoft Azure Fundamentals (AZ-900) — In progress

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