Senior Java Developer - Core Banking

Senior Java Engineer – Core Banking6-month contractFully RemoteCore banking experience is essential to be considered We are looking for a Senior Java Engineer to join a major Core Banking team delivering the development, modernisation and support of mission-critical banking services.You will work across several strategic initiatives, including core banking transformation, legacy-system modernisation, regulatory enhancements and integrations between core banking platforms and surrounding services.This is a hands-on engineering position requiring strong Java expertise and recent experience delivering highly available systems within banking, payments or financial services.Key responsibilitiesDesign, develop and maintain Java and Spring Boot services supporting core banking operations.Modernise legacy banking applications into scalable microservices.Build APIs and event-driven integrations between core banking platforms, payment systems and third-party services.Develop services covering areas such as accounts, balances, transactions, payments, reconciliation and regulatory reporting.Maintain transaction integrity, resilience, security and performance.Implement automated unit, integration and contract testing.Troubleshoot production incidents and perform root-cause analysis.Participate in code reviews, technical design and architecture discussions.Collaborate with architects, product owners, analysts and other engineering teams.Support the delivery of regulatory and compliance-driven banking changes.Essential experienceStrong commercial Java development experience, ideally Java 17 or 21.Extensive experience with Spring Boot and microservices.Recent experience within core banking, digital banking, payments or financial services.Experience building mission-critical, high-volume transactional systems.Strong REST API and systems-integration experience.Event-driven development experience using Kafka or similar technologies.Strong SQL and relational-database knowledge, such as PostgreSQL or Oracle.Understanding of distributed-system patterns, including idempotency, retries, reconciliation and failure recovery.Automated testing experience using JUnit, Mockito, Testcontainers or equivalent tools.Experience with Docker, Kubernetes and CI/CD pipelines.Strong communication skills and the ability to work within an international delivery team.Desirable experienceExperience with platforms such as Temenos Transact/T24, Oracle FLEXCUBE, Finacle, FIS, Fiserv, Mambu, Avaloq or a bespoke core banking system.Core banking transformation, migration or legacy-modernisation experience.Knowledge of account servicing, ledgers, balances and transaction posting.SEPA, SWIFT, Faster Payments, CHAPS, BACS, Instant Payments or ISO 20022 experience.AWS, Azure or GCP experience.Exposure to regulatory initiatives such as PSD2, Open Banking, DORA, AML or GDPR.Production support or on-call experience for critical banking services.This is an excellent opportunity to join a significant banking transformation programme and work with modern Java, cloud and distributed-system technologies.