Expert Software Engineer Mainframe AMS

About Us (Ensono)

Ensono is an expert technology adviser and managed service provider. As a relentless ally, we accelerate clients’ digital transformation to achieve business outcomes that stand to last. Our dedicated team helps organizations optimize today’s systems across any hybrid environment with services such as consulting, mainframe and application modernization, public cloud migration and cloud-native development. With certified experts in AWS, Azure and Google Cloud and recognized as Microsoft Datacenter Transformation Partner of the Year, Ensono has over 3500+ associates globally and is headquartered in greater Chicago. We care about your success, offering comprehensive strategic and managed services for mission-critical applications. Our Advisory and Consulting services can help upfront with an application strategy or find the right places for your applications – whether it’s public, multi or hybrid cloud, or mainframe. And because we span across all mission-critical platforms, we can meet you wherever you are in your digital transformation journey, with 24/7 support when you need it. We are your relentless ally, flexing with you when challenges emerge so you don’t feel stuck in place. With cross-platform certifications and decades of experience, our technology experts have become an extension of your team so you’re continuously innovating – doing more with less while remaining secure. And that’s just the beginning.

The Mainframe Expert Software Engineer – AMS is the highest technical tier within Ensono’s Mainframe Application Engineer job family, operating as a Subject Matter Expert (SME) across the full Application Managed Services lifecycle. This role is responsible for the end-to-end support, development, maintenance, testing, and modernisation of mission-critical mainframe applications for Ensono clients, delivered in alignment with contractual SLAs and ITIL-based service management processes.

This individual acts as a technical authority, escalation point, and knowledge anchor within the AMS delivery team — ensuring high availability of client applications, driving continuous service improvement, and enabling modernisation initiatives such as DevOps on Z and COBOL upgrades.

Roles & Responsibilities

• Provide 24×7 production support for mainframe applications, managing and resolving P1–P4 incidents in accordance with agreed SLAs
• Act as the escalation point (AMS Level 3) for complex incidents, problems, and application failures
• Perform root cause analysis and drive permanent problem resolution to reduce incident recurrence
• Pinpoint and remediate chatty or breaking transactions in hybrid application flows using App Performance Monitoring (APM) tools
• Design, develop, and maintain mainframe applications, including COBOL batch and online programs (CICS/IMS DC).
• Must have experience in Netron Framework.
• Execute application change requests, enhancements, and break/fix remediation within Change Management controls
• Lead and contribute to COBOL upgrade activities (VS COBOL through to IBM COBOL V6), including code retrofit, unit testing, system testing, and integration testing
• Manage application DB maintenance including DB2, IMS DB, and VSAM file structures
• Develop and maintain up-to-date application documentation, including functional logic, data lineage, and system schematics
• Support and evolve CI/CD pipeline activities within the DevOps on Zlifecycle — including static code analysis, automated unit testing, regression testing, and deployment to test, staging, and production environments
• Utilise GitHub with IBM DBBor GitHub with Endevor (Webhook/Git Bridge) for source code management
• Enforce quality gates (pass/fail) and drive automated test coverage improvements
• Lead knowledge acquisition, shadow, and reverse-shadow activities during AMS onboarding and client transition phases
• Create and maintain the Knowledge Management Framework documentation required for steady-state delivery
• Mentor Associate and Senior-level engineers; support capability development and knowledge retention within the team

Required Skills & Experience Technical

• Advanced COBOL programming (IBM Enterprise COBOL V4–V6), including batch and online environments
• CICS transaction processing — design, development, debugging, and tuning
• JCL authoring and optimisation, including batch scheduling concepts
• DB2— SQL development, application DBA tasks, query optimisation
• IMS DB/DC— application development and support
• VSAM— file design, management, and performance tuning
• z/OS platform understanding — sufficient to interpret system logs, dumps, and SMF data for application-level troubleshooting
• Assembler knowledge (desirable, not mandatory at application level)
• Modern SCM: GitHub, IBM Dependency Based Build (DBB) Modern IDE experience (e.g. IBM Wazi Developer, VS Code extensions for Z) Automated testing tools and frameworks for mainframe (e.g. IBM Developer for z/OS, Topaz)
• CI/CD pipeline concepts and execution in a mainframe context

Qualifications:

• Education: Bachelor’s or Master’s degree in Computer Science, Information Technology, or a related field.
• Experience: Extensive experience in mainframe application development, support and maintenance
• Soft Skills: Excellent problem-solving and analytical skills. Strong communication and interpersonal skills. Ability to work independently and as part of a team.

Shift Time – Rotational Shift – 24/7

We are an equal opportunity employer. All qualified applicants will be considered for employment without regard to caste, colour, creed, religion, gender, gender identity, sexual orientation, age, disability, HIV status, or any other status protected by law. Candidates with disabilities who require accommodations during the recruitment process are encouraged to contact our Talent Acquisition team to place a request.