Principal Java Engineer in London

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. 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 or US 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.

Join Our Global Team: We invite you to apply for the position at RE Partners. Join us in shaping the future of business technology consulting and transforming the way organizations thrive in a digital world. As a diverse, woman‑owned global business, we pride ourselves on keeping talent happy – our 7% attrition rate speaks volumes. Bring your talented friends along and earn a referral bonus.

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.

Salary Range: The base salary range for this role is $50,000–$200,000 per year. This is our good‑faith estimate at the time of posting. Actual base pay will depend on factors such as skills, experience, and location. This role may also be eligible for additional compensation (e.g., bonus/equity) and benefits, as applicable.