Mainframe Integration Engineer
We’re supporting a major digital banking programme and looking for an experienced Mainframe Integration Engineer to help modernise mission-critical payment systems. This role sits across legacy and modern stacks - linking CICS/Db2 on z/OS with Java/Spring APIs on AWS.
This will be Hybrid London (two days a week, but flexible), Inside Ir35 and a long term contract.
What you’ll work on :-
Core Mainframe Engineering
* Engineering CICS transactions, Db2 stored procedures and batch flows (JCL/REXX)
* Working with MQ, VSAM, GDGs, copybooks and mainframe data structures
IBM DataPower & API Mediation
* Configuring MPGW & WSP services
* Implementing AAA, OAuth2/JWT, MTLS, WS-Security policies
* Building transformations (XSLT/GatewayScript)
Mainframe and Cloud Integration
* Integrating with AWS API Gateway / TYK
* Building Java/Spring Boot microservices aligned to payment services
Essential experience:
* 12+ years with z/OS, CICS and Db2
* Strong JCL, REXX, VSAM, GDG, MQ
* Knowledge of COBOL/Assembler (reading/debugging)
* Experience with CICS channels, containers, pipelines and web services
* Db2 performance tuning (BIND, EXPLAIN, RUNSTATS)
Nice to have:
* Java 17+, Spring Boot
* AWS (Aurora PostgreSQL, API Gateway)
* ISO 20022, Faster Payments, BACS, CHAPS