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

It's fun to work in a company where people truly BELIEVE in what they're doing! 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 behaviorPerform deep root cause analysis for performance, system failures, and security exposuresWork with JCL, ISPF, SDSF, and system utilities to debug and validate behaviorCollaborate with engineering and support teams on L3 escalations and product fixesContribute to tooling, automation, and modernization effortsApply modern development practices (Git, AI-assisted debugging/workflows) Required Qualifications Minimum 10 years of experience in z/OS environmentsStrong expertise in: HLASM (Assembler) z/OS internals (mandatory)Hands-on experience with: JCL, ISPF, SDSF Batch job debugging and system diagnosticsProven experience in: Collecting and analyzing GTF traces (required) Debugging low-level system issuesStrong understanding of: APF authorization, SVC, PC, memory and execution model z/OS security concepts (RACF awareness)Experience with Git or modern version controlStrong problem-solving, debugging, and analytical skills Highly Desirable REXX scripting experienceKnowledge of: System exits, hooks, and intercepts Performance tuning and advanced diagnosticsExposure to: DB2, VSAM, or system-level data structuresExperience supporting customer escalations / L3 roles Work Model Collaborate with global (US-based) teamsFlexibility for overlapping time zones when requiredOperate with high ownership and minimal supervision 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: 781-577-4321 or send an email to people@rocketsoftware.com. 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! .