Senior Software Engineer – Mainframe Development

About the role

As a member of Mastercard’s Mainframe Services team in Copenhagen, you will help modernise and maintain the core transaction processing systems that support billions of payments worldwide. The role focuses on ensuring reliability, scalability and security of the Betalingsservice platform.

Key responsibilities

• Design, develop and maintain COBOL, JCL and DB2 applications on IBM z/OS.
• Collaborate with cross‑functional teams to integrate mainframe services with distributed systems.
• Lead modernisation initiatives, including migration to event‑driven architectures and API enablement.
• Ensure compliance with Mastercard’s Mainframe Security Technical Standard and participate in daily change‑request syncs.
• Contribute to the Software Engineering Guild’s standards and perform on‑call duties outside regular hours.

Required profile

• 5+ years of experience in mainframe development (COBOL, JCL, DB2, SQL).
• Strong understanding of IBM z/OS architecture and batch processing.
• Experience with file‑transfer gateways and integration layers.
• Familiarity with Agile methodologies and ability to work in a global, distributed team.
• Passion for modernisation and continuous improvement; bonus knowledge of Mastercard’s Bill Pay products.

Required skills

• COBOL
• JCL
• DB2
• IBM z/OS
• SQL
• File transfer gateways
• Agile methodologies
• API enablement
• Event‑driven architecture concepts