Senior Core Java Engineer – Low Latency, -Throughput Systems

Senior Core Java Engineer – Low Latency, High-Throughput Systems

We are looking for a deeply experienced and opinionated Senior Java Engineer to join a high‑performance team working on next‑generation, low‑latency payment systems.

This is a hands‑on role for engineers who are passionate about performance, clean architecture, and real‑time processing in a financial technology environment. If you thrive on building scalable, high‑throughput platforms using Core Java and modern cloud‑native tooling, we want to hear from you.

• Design, develop, and optimise low‑latency backend services using Core Java and Spring Boot
• Build and maintain RESTful APIs and microservices for secure payment workflows
• Work with XML‑based messaging standards common in financial systems
• Deploy, monitor, and scale applications in Red Hat Open Shift and AWS
• Integrate with MongoDB and other data stores for real‑time data handling
• Drive performance tuning, fault tolerance, and observability across services
• Collaborate in architectural discussions and advocate for engineering best practices

• 5+ years of Core Java development with a focus on performance and memory optimisation
• Proven experience building low‑latency, high‑throughput systems (sub‑millisecond experience a plus)
• Strong proficiency in Spring Boot and microservices architecture
• Hands‑on experience with XML parsing/transformation and message protocols
• Experience deploying on Red Hat Open Shift/Kubernetes and strong AWS cloud familiarity
• Knowledge of MongoDB or similar No
  
  SQL databases
• Background in Payments, Financial Services, or Banking systems
• Strong communication skills and an opinionated, collaborative approach to engineering

• Experience with messaging systems (Kafka, Rabbit
  
  MQ)
• Knowledge of payment gateways,
  ISO 20022
  , or SWIFT formats
• Exposure to container security and performance tuning in Open Shift

• A collaborative, engineering‑led culture with an emphasis on autonomy and clean code
• Opportunity to work on high‑impact, real‑time systems in payments technology
• Hybrid working model based in the UK

• Location:
  
  London, England, United Kingdom
• Seniority level:
  Mid‑Senior level
• Employment type:
  
  Full‑time
• Job function:
  Engineering and Information Technology

Please apply only if you have a current legal status to work in the UK. This role does not offer visa sponsorship.

Interested? Let’s connect.

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