Principal Java Engineer

RE Partners; Greater London; Hybrid; GBP 120,000 - 180,000; Full time

Job summary

RE Partners in the United Kingdom seeks an experienced Principal Java Engineer to join our high-performing engineering team. You will design, implement, and optimize low-latency, high-throughput backend services in the payments domain, using modern Java and SpringBoot in a hybrid UK-based role.

You will deploy and scale systems in OpenShift and AWS, integrate with MongoDB, and mentor peers while driving architecture and observability across services.

Qualifications

• 10+ years of Java development with a focus on performance and memory optimization.
• Proficient with MongoDB, Spring, and microservice-based architectures.
• Experience with low-latency, high-throughput applications and real-time data.
• Hands-on deploying on OpenShift and/or Kubernetes, plus AWS cloud services.

Responsibilities

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

Skills

Java performance

Microservice architecture

System architecture

High-throughput design

Tools

MongoDB

OpenShift

Kubernetes

AWS (ECS/EKS/Lambda/S3)

Job description

Who We Are:

We are a fast growing business and technology consultant company co-founded in 2019. We offer a custom-tailored, white-glove engineering service fit for our clients, because a digital transformation is more than just technology. With a successful track record of being a preferred vendor for Fortune 500 companies and as a trusted partner for some of the industry’s leading companies, our global talent has helped many clients achieve their goals.

The 3 G’s of RE:

“Get Shit Done.”

“Get Over Shit.”

“Give a Shit.”

Principal Java Engineer

We are seeking an experienced and opinionated Principal Java Engineer to join our high-performing engineering team, working on low latency, high-throughput systems in the payments processing domain. This hybrid role is based in the UK and offers the opportunity to build scalable, real-time services using modern technologies. If you’re passionate about performance, have strong Core Java and SpringBoot expertise, and thrive in a collaborative yet opinionated engineering culture, we want to hear from you.

Key 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 commonly used in financial transactions.
• Deploy, monitor, and scale applications in Red Hat OpenShift and AWS cloud environments.
• Integrate with MongoDB and other NoSQL/SQL datastores for real-time data management.
• Collaborate with DevOps, Product, and QA teams to ensure production-grade solutions.
• Drive architectural changes, advocate for best practices, and provide mentorship to peers.
• Drive performance tuning, fault tolerance, and observability improvements across services.

Required Skills & Experience:

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

Nice to Have:

• Familiarity with messaging systems (Kafka, RabbitMQ, etc.)
• Prior experience in Payments Processing, financial services, or banking systems.
• Exposure to container security and performance tuning on OpenShift.
• Knowledge of payment gateways, ISO 20022, or SWIFT formats.
• Hybrid work model in London, UK.
• Collaborative, fast-paced, and engineering-driven culture.
• Emphasis on engineering autonomy, architectural decision-making, and clean code

Equal Opportunity Employer:

We are an equal opportunity employer and welcome applications from all qualified individuals regardless of race, color, religion, gender, sexual orientation, gender identity or expression, national origin, age, disability, or veteran status.