Java Developer

London 30 days agoContractor External
Negotiable
This job posting has expired and is no longer accepting applications.
Java Developer Hybrid Working - Local - 1-2 days a week on site. Financial Services Lorien's leading banking client is looking for a Java Developer who thrives on delivering low‑latency, scalable services and event‑driven architectures. If you're experienced with Java, Apache Kafka, OpenShift, and have a strong understanding of payments (cards, international payments ). This role is based in a local office. This role will be Via Umbrella. Working in a Hybrid Model of 2 days a week on site. What you'll do • Design, build, and maintain microservices in Java (preferably Java 11+ / 17) for mission‑critical payment flows. • Develop event‑driven solutions using Kafka (producers/consumers, schema management, stream processing). • Deploy and operate services on OpenShift (Kubernetes-based), including CI/CD pipelines, configuration, scaling, and observability. • Implement robust error handling, idempotency, retries, and exactly-once/at-least-once delivery where appropriate. • Ensure security, compliance, and auditability across the payments lifecycle (encryption, secrets management, logging). • Collaborate with product, QA, SRE, and architecture teams to deliver high‑quality features in iterative releases. • Contribute to performance tuning, resilience testing, and SLAs/SLOs for real‑time processing. • Write clean, testable code with unit, integration, and contract tests; participate in code reviews. What you'll bring • Strong core Java skills (collections, concurrency, JVM fundamentals) and experience building production microservices (Spring Boot/Quarkus/Micronaut). • Hands‑on expertise with Kafka (topics, partitions, consumer groups, schema registry/Avro/JSON, Kafka Streams/KSQL is a plus). • Practical experience deploying to OpenShift (routes, deployments, operators) or Kubernetes (Helm, manifests). • Solid understanding of payments: funds movement, reconciliation, authorisation/capture, settlement, chargebacks, or real‑time payments (e.g. Faster Payments/SEPA Instant). Familiarity with ISO 8583/ISO 20022, PCI basics, or PSD2/Open Banking is beneficial. • Exposure to CI/CD (GitHub Actions/Jenkins/Argo), containerisation (Docker), and observability (Prometheus/Grafana/ELK/OpenTelemetry). • Experience with databases (SQL/NoSQL), caching (Redis), and message semantics (idempotency, deduplication). • A collaborative mindset, ownership of outcomes, and a passion for building resilient, scalable systems. Nice to have • Experience with Hazelcast, Kafka Connect, Schema Registry, or Confluent Platform. • Knowledge of security in payments: OAuth2/OpenID Connect, mTLS, HSMs, tokenisation. • Background in performance engineering (JMH, Gatling, k6) and chaos/resilience testing. • Cloud experience (AWS/GCP/Azure) and infrastructure‑as‑code (Terraform/Ansible). • Domain experience in card acquiring, issuer processing, merchant services, AML/fraud, or risk engines. IND_PC3 Guidant, Carbon60, Lorien & SRG - The Impellam Group Portfolio are acting as an Employment Business in relation to this vacancy.