Software Engineer III (Mainframe Assembler(HLASM)- z/OS Security & Systems (zAssure Portfolio)

Job Description

Summary:Rocket Software is seeking a Mainframe Engineer to join the zAssure Security Portfolio team. This role focuses on deep system-level engineering, security analysis, and advanced diagnostics within z/OS environments.

This is a highly specialized role requiring strong expertise in z/OS internals, HLASM (Assembler), and system-level debugging. The role combines product engineering with complex troubleshooting and customer-facing escalation support, making it critical to the success of our security solutions.

The ideal candidate brings hands-on experience working with low-level system constructs, the ability to diagnose complex production issues, and a strong ownership mindset.

Key Responsibilities

• Design, develop, and maintain HLASM-based components for z/OS security and system tooling (VAP and related products)
• Diagnose complex issues using z/OS diagnostic tools (including GTF traces)
• Analyze APF-authorized programs, SVCs, PC routines, and system behavior
• Perform deep root cause analysis for performance, system failures, and security exposures
• Work with JCL, ISPF, SDSF, and system utilities to debug and validate behavior
• Collaborate with engineering and support teams on L3 escalations and product fixes
• Contribute to tooling, automation, and modernization efforts
• Apply modern development practices (Git, AI-assisted debugging/workflows)



Required Qualifications

• Minimum 10 years of experience in z/OS environments
• Strong expertise in: HLASM (Assembler) z/OS internals (mandatory)
• Hands-on experience with: JCL, ISPF, SDSF Batch job debugging and system diagnostics
• Proven experience in: Collecting and analyzing GTF traces (required) Debugging low-level system issues
• Strong understanding of: APF authorization, SVC, PC, memory and execution model z/OS security concepts (RACF awareness)
• Experience with Git or modern version control
• Strong problem-solving, debugging, and analytical skills



Highly Desirable

• REXX scripting experience
• Knowledge of: System exits, hooks, and intercepts
• Performance tuning and advanced diagnostics
• Exposure to: DB2, VSAM, or system-level data structures
• Experience supporting customer escalations / L3 roles



Work Model

• Collaborate with global (US-based) teams
• Flexibility for overlapping time zones when required
• Operate with high ownership and minimal supervision
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Rocket Software Inc. is committed to creating a diverse environment and is proud to be an equal opportunity employer. All qualified applicants will receive consideration for employment without regard to race, color, religion, gender, gender identity or expression, sexual orientation, national origin, genetics, disability, age, or veteran status. Rocket Software Inc. is also committed to compliance with all fair employment practices regarding citizenship and immigration status.

As part of our commitment to a safe and trustworthy workplace, we include background and reference checks in our hiring process.

Rocket is committed to working with and providing reasonable accommodation to individuals with physical and mental disabilities. If you need special assistance or an accommodation while seeking employment, please call: or send an email to We will make a determination on your request for reasonable accommodation on a case-by-case basis.

If you like wild growth and working with happy, enthusiastic over-achievers, you'll enjoy your career with us!