IBM Mainframe COBOL Developer (z/OS, AS/400)

SREE VINEETH DUNNA

MAINFRAME / COBOL DEVELOPER IBM z/OS & IBM iSeries (AS/400)

Lincoln, Nebraska +1-913-***-**** *************@*****.***

PROFESSIONAL SUMMARY

Mainframe and COBOL Developer with 5+ years of experience developing, enhancing, testing, deploying, and supporting mission-critical Banking, Financial Services, and Insurance applications across IBM z/OS and IBM iSeries (AS/400). Strong hands-on experience with COBOL, JCL, DB2, IMS DB, CICS, VSAM, CA7, REXX, TSO/ISPF, batch processing, production support, and real-time transaction processing. Experienced in COBOL compile, link-edit, DB2 precompile and package bind/rebind processes, DBRM validation, load-module management, JCL/PROC development, batch scheduling, abend analysis, incident resolution, root cause analysis, software migration, release implementation, and support across Development, QA, UAT, and Production. Proven cross-functional collaboration with DBA, CICS, Infrastructure, Operations, Scheduling, QA, business, and support teams in Agile and Waterfall environments.

TECHNICAL SKILLS

Mainframe Technologies: COBOL, JCL, IBM z/OS, IBM iSeries/AS400, CICS, TSO/ISPF, SDSF, REXX

Databases & Files: DB2, IMS DB, SQL, DB2 Stored Procedures, VSAM

COBOL Build & Deployment: Compilation, DB2 Precompile, Link-Edit/Linking, Binding/Rebinding, DBRM Validation, Load Module Management, Package Management

JCL, Batch & Scheduling: JCL, PROCs, Control Cards, Batch Processing, Batch Monitoring, Job Scheduling, CA7, Abend Analysis, Restart/Recovery Support

Mainframe Utilities: IDCAMS, IEBGENER, DFSORT, SYNCSORT, SPUFI, IKJEFT01, File-AID, Expeditor, Easytrieve

Testing & Support: Unit Testing, Integration Testing, System Testing, Regression Testing, L2/L3 Production Support, Incident Management, Root Cause Analysis, Troubleshooting

Release & Operations: ChangeMan, Release Management, Change Management, Software Migration, Application Deployment, Environment Management, Production Readiness

Integration & Tools: REST APIs, .NET Integration, GitHub, Jira, Postman, IBM Data Studio

Cloud & AI: AWS, Azure, GitHub Copilot, Cognition Devin, GPT-6 Astra, AI-Assisted Code Analysis

PROFESSIONAL EXPERIENCE

Orion Innovation Fiserv

Mar 2025 - Present

COBOL Developer

Lincoln, Nebraska

Project: Real Time Banking Modernization Modernizing batch-dependent banking processing with real-time transaction capabilities.

• Develop, enhance, unit test, and support real-time COBOL applications on IBM iSeries (AS/400), help transition banking workflows from overnight batch dependency toward real-time transaction processing.

• Analyze business and technical requirements, perform impact analysis, prepare technical designs, code application changes, execute testing, participate in peer reviews, and support implementation through the SDLC.

• Integrate IBM iSeries applications with .NET services through REST APIs and validate interfaces using Postman, enabling communication between legacy banking components and modern services.

• Work with DB2 and SQL for application data access, analysis, troubleshooting, and validation of application changes.

• Manage GitHub branching, version control, pull/code reviews, and deployment coordination for application releases.

• Perform application debugging, defect analysis, issue resolution, and production-readiness validation in collaboration with business analysts, architects, infrastructure teams, and stakeholders.

• Use GitHub Copilot and Cognition Devin for code analysis, debugging, impact assessment, code review, and technical documentation.

• Worked hands-on with IBM z/OS mainframe applications using COBOL, JCL, VSAM, and DB2 to support banking processing alongside IBM iSeries (AS/400) development.

• Developed, enhanced, tested, and supported COBOL programs and JCL batch jobs; used DB2/SQL for application data access and VSAM datasets for file-based processing and validation.

• Provided batch and production support by monitoring application jobs, analyzing job failures and abends, troubleshooting COBOL/JCL, DB2, and VSAM issues, and supporting restart/recovery and incident resolution.

• Used mainframe tools and utilities including TSO/ISPF, SDSF, File-AID, DFSORT/SYNCSORT, IDCAMS, and ChangeMan for job monitoring, dataset/file analysis, troubleshooting, and application migration/release support.

Environment: COBOL, JCL, IBM z/OS, IBM iSeries (AS/400), DB2, SQL, VSAM, TSO/ISPF, SDSF, File-AID, DFSORT/SYNCSORT, IDCAMS, ChangeMan, GitHub, REST APIs, .NET, Postman, Jira, Agile

Datics

Aug 2024 - Mar 2025

Mainframe Developer

Overland Park, Kansas

Project: Adjustments Application Enterprise claim-adjustment processing supporting correction of claims affected by invalid input or incorrect data setup during adjudication.

• Developed, enhanced, tested, and supported COBOL, DB2, JCL, and CICS programs for enterprise claim-processing applications.

• Developed and maintained JCL, PROCs, control cards, and batch workflows supporting high-volume processing; monitored scheduled jobs and resolved execution and dependency issues.

• Analyzed COBOL/JCL application abends, batch failures, DB2 errors, data issues, and production incidents; performed root cause analysis, implemented corrective changes, and validated recovery.

• Supported COBOL application build and release activities, including compile/link processes, DB2 package bind/rebind, DBRM validation, and migration of application components across environments.

• Reviewed SQL statements, DB2 execution behavior, and workload performance to support database troubleshooting and application performance analysis.

• Performed unit, integration, system, and regression testing, prepared test data, validated results, and supported defect resolution prior to production deployment.

• Supported release implementation, ChangeMan migrations, software deployment, change-management validation, and environment management across Development, QA, UAT, and Production.

• Automated repeatable operational processes using REXX, reducing manual support effort and improving execution consistency.

• Provided production support through batch monitoring, incident troubleshooting, application support, and coordination with DBA, CICS, Infrastructure, Operations, Scheduling, onshore/offshore, and business teams.

Environment: COBOL, DB2, JCL, CICS, CA7, VSAM, IMS DB, REXX, TSO/ISPF, ChangeMan

IBM (Artech) Bank of Montreal (BMO)

Feb 2021 - Dec 2022

Mainframe Developer

Hyderabad, Telangana

Project: CFM / IPS Mainframe banking application development, batch processing, and production support.

• Provided L2/L3 production support for business-critical mainframe IMS/DB applications, supporting system availability, operational stability, incident resolution, and service restoration.

• Monitored daily and scheduled batch cycles; analyzed job failures, job dependencies, scheduling issues, performance bottlenecks, application abends, and restart/recovery requirements.

• Developed and maintained COBOL programs, JCL, PROCs, and control cards; managed CA7 scheduling dependencies and resolved batch execution issues.

• Performed COBOL compilation, DB2 precompile/build activities, link-edit/linking and binding, DB2 bind/rebind, DBRM validation, package support, and load-module management for application changes and releases.

• Used TSO/ISPF, SDSF, DB2, IMS DB, CICS, VSAM, and mainframe utilities to review job output, troubleshoot failures, debug applications, validate datasets, and investigate production issues.

• Supported Development, QA, UAT, and Production migrations, including ChangeMan implementation, software releases, implementation planning, production-readiness checks, and post-deployment validation.

• Worked with CICS transactions and batch components to troubleshoot performance and processing issues; managed VSAM datasets and supported data migration activities across environments.

• Collaborated with DBA, CICS, Scheduling, Infrastructure, Operations, and application teams and provided after-hours/weekend support for critical production releases and maintenance activities.

Environment: COBOL, JCL, DB2, IMS DB, VSAM, CICS, CA7, TSO/ISPF, SDSF, ChangeMan, IBM Data Studio, REXX, z/OS

SELECTED PROJECTS

Website Builder: Led front-end development using HTML, CSS, Bootstrap, JavaScript, and React; implemented backend functionality with Python and MongoDB.

Housing Community Management System: Designed and implemented a web-based management system with a user-friendly interface and Python/MongoDB backend functionality.

Inventory Management System: Designed a cloud-based inventory platform using Azure and AWS services including Azure Storage, Azure DevOps, EC2, S3, CloudFormation, and RDS.

EDUCATION

University of Central Missouri

Jan 2023 - May 2024

Master of Computer Science

Pragati Engineering College

Jun 2016 - Apr 2020

Bachelor of Technology, Information Technology

CERTIFICATIONS

• IBM Master the Mainframe Certification

• Python and C++ Certification - NPTEL, IIT Kharagpur

• Internet of Things (IoT) Certification - Coursera with APSSDC

Contact this candidate