> Markdown version of [/jobs/ext/4544221-mainframe-assembler-developer](https://www.wearedevelopers.com/jobs/ext/4544221-mainframe-assembler-developer). Every page supports `.md` or `Accept: text/markdown`. Links point to the HTML versions so they work for humans too. Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md).

---

# Mainframe Assembler Developer

- **Company:** EXPERT RECRUITING SOLUTIONS, LLC
- **Location:** Summit, NJ, United States
- **Experience:** Expert
- **Contract:** Permanent contract
- **Skills:** Batch Processing, IBM Parallel Sysplex, Job Control Language (JCL), IBM Mainframe, Mainframes, Software Engineering, Virtual Storage Access Methods, Z/OS, Tso/ispf, GitHub Copilot, Servicenow
- **Published:** November 3, 2026
- **Apply:** https://www.thejobnetwork.com/job/93b94fee-95e7-42b9-ba57-32eabf48af57/mainframe-assembler-developer

## About the Role

We are seeking a highly experienced Mainframe Assembler Developer to support and enhance a mission-critical legacy application written in IBM z/OS assembler language. This role requires a self-sufficient engineer capable of independently analyzing, maintaining, and improving high-volume, high-availability batch processing systems in a regulated financial services environment. The ideal candidate brings deep expertise across core mainframe technologies and strong familiarity with parallel sysplex environments., Experience: 5 years of experience in IBM Mainframe application development and production support.

Technical Skills:

 * Assembler (HLASM) programming
 * JCL/ECL development and troubleshooting
 * TSO / ISPF environment
 * Connect:Direct (NDM)
 * ISPW (or equivalent change management tools)
 * CA7 scheduling
 * GitHub CoPilot
 * Mainframe datasets, VSAM, and utilities

## Description

* Analyze, maintain, and improve high-volume, high-availability batch processing systems.
 * Provide production support for IBM Mainframe applications.
 * Develop and troubleshoot JCL.
 * Manage GDGs and batch processing to meet strict SLAs.
 * Work independently within loosely documented legacy environments.
 * Analyze complex assembler codebases to diagnose and resolve critical production issues.
 * Handle incident management using tools like ServiceNow or Remedy.