Java Developer

Lorien; Greater London; Hybrid; GBP 55,000 - 70,000; Full time

Job summary

A leading financial services firm is seeking a Java Developer to design and maintain low-latency microservices for payment flows. You will develop event-driven solutions using Kafka and deploy services on OpenShift. Candidates should have strong Java skills, hands-on experience with Kafka, and an understanding of payments. This hybrid role requires 1-2 days a week on site, offering flexibility along with competitive compensation.

Qualifications

• Experience building production microservices.
• Hands-on expertise with Kafka topics and consumer groups.
• Practical experience deploying to OpenShift or Kubernetes.

Responsibilities

• Design and maintain microservices in Java for payment flows.
• Develop event-driven solutions using Kafka.
• Deploy services on OpenShift with CI/CD pipelines.

Skills

Core Java skills (collections, concurrency, JVM fundamentals)

Hands-on expertise with Kafka

Practical experience deploying to OpenShift or Kubernetes

Understanding of payments (funds movement, reconciliation)

Exposure to CI/CD

Experience with databases (SQL/NoSQL)

Collaborative mindset

Tools

Spring Boot

Docker

Prometheus

Grafana

Job description

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 life cycle (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 (eg 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.