Systems Mainframe Engineer​/Postilion

We are seeking a highly experienced Senior Base
24 Payments Engineer to join the Legacy Base
24 team supporting the existing ATH platform. This role is ideal for a seasoned payments professional with deep expertise in card processing, authorization systems, and transaction routing who can contribute strategically beyond hands-on development.

The successful candidate will play a key role in maintaining and enhancing critical payment processing systems while providing architectural guidance and technical leadership across the platform.

• Support and enhance the legacy ACI Postilion(formerly Base
  24) environment supporting the ATH platform.
• Design, develop, and maintain payment transaction processing solutions.
• Provide expertise in authorization routing, debit network integrations, and card transaction processing.
• Collaborate with technical and business stakeholders to evaluate and implement system improvements.
• Contribute to architecture discussions and provide recommendations for platform modernization and optimization.
• Troubleshoot and resolve complex production issues related to payment processing systems.
• Ensure compliance with security, encryption, tokenization, and payment industry best practices.
• Support integration efforts across mainframe and distributed platform environments.

Required Qualifications

• Extensive experience with Base
  24 (TAL) or Postilion
• Deep knowledge of card processing and electronic payments systems.
• Experience with:
  • Authorization routing
  • Debit networks
  • Payment switching and transaction processing
  • Payment platform architecture
• Strong understanding of:
  • Encryption technologies
  • Tokenization
  • Payments security concepts
• Hands-on development experience in COBOL mainframe environments with JCL, CICS, DB2
• Must have an architectural mindset and strong troubleshooting abilities, with experience navigating mainframe environments, analyzing COBOL/CICS applications, performing root cause analysis, reverse engineering complex issues, and assessing the downstream impact of system changes.
• Experience working within Windows-based platforms.
• Ability to analyze complex systems and provide architectural guidance and recommendations.
• Excellent problem-solving and communication skills.???????