Principal Java Engineer - Low-Latency Payments Systems

RE Partners; Warszawa; Hybrid; PLN 454,000 - 655,000; Full time

Benefits offered by this job

Hybrid work model in Warsaw, Poland

Job summary

RE Partners is seeking an experienced Principal Java Engineer to join our high-performing engineering team. You will work on low-latency, high-throughput backend systems in the payments processing domain, with hybrid work based in the UK.

You will design and optimize services, build secure payment workflows, and scale infrastructure across OpenShift, AWS, and diverse data stores while mentoring peers in an opinionated engineering culture.

Qualifications

• 10+ years of Java development experience focusing on performance and memory optimization.
• Proficient in Mongo, Spring and microservice-based architecture.
• Experience with low-latency, high-throughput applications (sub-millisecond response times a plus).
• Hands-on experience deploying applications on OpenShift and/or Kubernetes.
• Strong cloud experience with AWS services (ECS, EKS, Lambda, S3, etc.).
• Excellent communication with bias toward action and opinionated design decisions.

Responsibilities

• Design, develop, and optimize low-latency, high-throughput backend systems using Java.
• Build and maintain RESTful APIs and microservices that power secure payment workflows.
• Work with messaging standards and protocols used in financial transactions.
• Deploy, monitor, and scale applications in OpenShift and AWS cloud environments.
• Integrate with MongoDB and other datastores for real-time data management.
• Collaborate with DevOps, Product, and QA to ensure production-grade solutions.
• Drive architectural changes, advocate best practices, and mentor peers.
• Drive performance tuning, fault tolerance, and observability improvements across services.

Skills

Java performance

Low-latency design

Microservices

REST APIs

Cloud computing

Tools

MongoDB

SpringBoot

OpenShift

Kubernetes

AWS

Job description

RE Partners is seeking an experienced Principal Java Engineer to join our high-performing engineering team. You will work on low-latency, high-throughput backend systems in the payments processing domain, with hybrid work based in the UK.

You will design and optimize services, build secure payment workflows, and scale infrastructure across OpenShift, AWS, and diverse data stores while mentoring peers in an opinionated engineering culture.