Strangler fig patterns, adapter layers, and modernisation strategies for integrating with core banking and legacy financial systems — without taking the bank offline.
Modernising integration with core banking: strangler fig, anti-corruption layer, MQ-CICS bridges, COBOL adapters, COMMAREA marshalling, EBCDIC handling, and cutover patterns.
Sequencing a multi-year migration: dependency analysis, capability slicing, parallel run patterns, IBM IIDR CDC configuration, reconciliation SQL, and the metrics that prove progress to stakeholders.
IBM IIDR and Debezium against DB2 on z/OS and IBM i, schema mapping, event envelope design, SAMA audit trail continuity, and the patterns for keeping legacy as system-of-record while shipping new product without polling.
PIC clause type mapping, packed decimal COMP-3 parsing, EBCDIC-to-UTF-8 conversion for Arabic fields, DFDL schema design in IBM ACE, and ESQL mapping for financial record structures — the practical guide to moving mainframe data into modern JSON services.
ACE ESQL SOAP envelope construction, IBM API Connect assembly SOAP proxy, OpenAPI 3.1 contract-first design with FAPI 2.0 security, SOAP fault-to-HTTP error mapping, and the strangler-fig approach to incrementally exposing legacy SOAP services as REST without rewriting the backend.
Big-bang cutovers fail for predictable reasons. Dual-write to DB2 and PostgreSQL simultaneously, shadow reads to validate without serving, Kafka as the synchronisation bus, and the exact cutover gate criteria that tell you when it is safe to switch writes at a KSA bank.