Senior Mainframe Developer

Senior Mainframe Developer

AG Consulting Partners, Inc. · Tacoma, United States (Hybrid) · Full-time · Posted 2026-10-12

Salary: USD 115,000–145,000

Workplace: hybrid

Department: Technology and Analytics

Description

About This Opportunity

We are seeking an experienced Senior Mainframe Developer to lead the remediation and modernization of a 50-year-old legacy COBOL system running on a Unisys mainframe platform. This role will be responsible for analyzing, modifying, and enhancing critical business applications to support integration with Workday Human Capital Management (HCM), Payroll, Finance, and related enterprise services.

This individual will work closely with enterprise architects, Workday integration developers, business analysts, infrastructure teams, and business stakeholders to enable reliable and secure data exchange between legacy applications and the Workday platform.

Key Responsibilities:

• Legacy System Assessment & Remediation
  • Analyze and document existing Unisys-based COBOL applications, batch processes, databases, interfaces, and data flows.
  • Review and assess approximately 50 years of application code for technical debt, dependencies, and remediation requirements.
  • Identify and resolve code defects, performance bottlenecks, and system integration constraints.
  • Refactor, modify, and enhance COBOL programs to support modern integration patterns.
  • Maintain business continuity while implementing system changes.
• Workday Integration Enablement
  • Design and implement integration solutions between legacy Unisys applications and Workday.
  • Create outbound interfaces for legacy data to Workday.
  • Develop inbound processes to consume Workday-generated data.
  • Support Workday APIs, web services, EIBs, and middleware-based integrations.
  • Design data transformation and validation processes to ensure data integrity.
• Data Analysis & Conversion
  • Analyze existing master and transactional data structures.
  • Map legacy data elements to Workday objects.
  • Identify data quality issues and develop remediation plans.
  • Support migration and reconciliation activities.
  • Develop automated processes for data extraction and transformation.
• Architecture & Modernization
  • Provide recommendations for modernization and technical roadmaps.
  • Identify opportunities to reduce technical debt and improve maintainability.
  • Implement best practices for application lifecycle management.
  • Document system architecture, interfaces, and operational procedures.
• Testing & Quality Assurance
  • Develop and execute unit, system, integration, and regression testing strategies.
  • Support end-to-end testing with Workday and external systems.
  • Ensure all modifications comply with security, audit, and regulatory requirements.
• Production Support
  • Provide support for production deployments.
  • Troubleshoot integration failures and batch processing issues.
  • Participate in on-call support during critical implementation periods.
  • Monitor system performance and recommend improvements.

Requirements

You have:

• Education
  • Bachelor's degree in Computer Science, Information Systems, Engineering, or a related field.
  • Equivalent combination of education and relevant experience may be considered.
• Experience
  • 10+ years of COBOL development experience.
  • 7+ years supporting enterprise mainframe environments.
  • 5+ years working with Unisys mainframe platforms.
  • Experience maintaining highly customized legacy applications over multiple decades.
  • Experience supporting large-scale modernization or digital transformation initiatives.
  • Experience integrating legacy systems with cloud-based SaaS platforms.
  • Experience with COBOL-74, COBOL-85, or Enterprise COBOL.
  • Experience with DMSII databases.
  • Experience with batch processing systems and JCL or equivalent job scheduling frameworks.
  • Experience with enterprise integration technologies, including REST APIs, SOAP web services, ETL processes, data mapping and transformation, middleware platforms, message queues, and secure file transfer solutions.
  • Experience with relational databases and SQL.
  • Experience with one or more of the following: Workday HCM, Workday Payroll, Workday Financials, Workday Studio, Workday Web Services (WWS), Enterprise Interface Builder (EIB), or Workday integration frameworks.

This job is for you if you possess:

• Technical Leadership
  • Experience mentoring junior and mid-level developers.
• Business Analysis Skills
  • Understanding of payroll, HR, finance, and workforce management business processes.
• Strong Communication
  • Experience communicating with executives, architects, business stakeholders, and technical teams.
• Legal Authorization
  • Eligible to work in the United States.

Benefits

About Us

AG Consulting Partners, Inc. is a Redmond-based boutique consulting firm. Our mission is to embrace the entrepreneurial spirit to relentlessly deliver an exceptional experience and results for our people and our clients.

We put our people first. Our excellent benefits to full-time employees include medical, dental, vision, PTO, 401K matching, education reimbursement, community and philanthropic events and flexible career paths.

We’re humbled to be consistently acknowledged by local and national organizations for our success, including Consulting Magazine, Puget Sound Business Journal, and Inc. 5000.

The compensation for this position is tailored to reflect your unique skill set, relevant experience, and the current dynamics of the job market. We strive to ensure that our compensation package is competitive and fair, taking into account various factors to provide a rewarding opportunity for our team members.

The annual salary range for this role is: $115,000 - $145,000 per year.

Apply

Apply at AG Consulting Partners, Inc.

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