Mainframe Middleware Engineer - 6-Month Contract - Hybrid (London, or Edinburgh)

Mainframe Middleware Engineer - 6-Month Contract - Hybrid (London, or Edinburgh)

We are seeking a Mainframe Middleware Infrastructure Engineer with strong expertise in CICS Liberty environments on z/OS. This role focuses on infrastructure engineering rather than application development, supporting modern, secure, and highly available Java workloads within CICS. You will work at the intersection of traditional Mainframe systems and contemporary integration and DevOps practices.

Key Responsibilities

• Provide deep systems engineering expertise across CICS running on z/OS, including runtime behavior and infrastructure design
• Configure, maintain, and optimize IBM WebSphere Liberty within CICS (CICS Liberty runtime)
• Design and support secure, scalable, and resilient CICS Liberty environments aligned with enterprise standards
• Manage integration patterns, including REST/HTTP APIs and modern service exposure

What You Will Ideally Bring

• Strong hands-on experience with CICS system setup and configuration (regions, JVM Servers)
• Solid understanding of z/OS components supporting CICS Liberty (USS, RACF, TCP/IP, SMF)
• Experience in capacity planning, performance tuning, and high availability/disaster recovery (HA/DR)
• Proven problem determination skills using dumps, traces, SMF data, and logs
• Expertise in WebSphere Liberty configuration (server.XML, features, shared libraries)
• JVM tuning on z/OS (heap sizing, garbage collection behaviour)
• Experience managing Java workloads within CICS (JVM server life cycle, diagnostics)

Contract Details

• Duration: 6 months (with potential extension)
• Day Rate: Up to £400 per day (Inside IR35)
• Location: - Hybrid (2 days onsite per week) - London or Edinburgh
• Start Date: ASAP