Principal Java Engineer

United States Digital Space LLC; Wallingford; On-site; GBP 90,000 - 130,000; Full time

Job summary

GTI is seeking a Principal Java Engineer to provide technical leadership for its core SaaS platform. Reporting to the CTO, you will own technical direction, architecture and engineering standards, without direct line management.

You will collaborate with Product, Data, Operations, DevOps and QA to deliver secure, resilient, and scalable solutions while mentoring engineers and promoting best practices across teams.

Qualifications

• Degree in Computer Science or equivalent experience.
• Extensive Java software engineering experience with significant leadership responsibilities.
• Expert knowledge of Java, JVM performance and modern language features.
• Deep experience with Spring Boot, Hibernate/JPA and enterprise app architecture.
• Strong understanding of distributed systems, scalability and performance tuning.
• Experience with cloud-native apps, Docker, Kubernetes and CI/CD.
• Knowledge of application security and OWASP principles.

Responsibilities

• Design, implement and review high-quality Java and full-stack solutions, APIs and integrations.
• Lead performance, scalability, security and resilience initiatives.
• Drive security practices and secure SDLC across teams.
• Mentor engineers and align architecture with product roadmaps.
• Lead root-cause analyses and improve production observability and reliability.
• Collaborate with Operations, DevOps and QA to ensure service quality.

Skills

Java

Spring Boot

Hibernate/JPA

Distributed systems

Cloud-native

CI/CD

Security practices

Technical leadership

Education

Degree in Computer Science

Tools

Tomcat

IntelliJ IDEA

RabbitMQ

OpenAPI

Angular

GitLab/Jenkins

AWS

Docker

Kubernetes

MySQL

Solr

Job description

Description

As Principal Java Engineer, you will provide technical leadership for GTI’s core SaaS platform. Reporting directly to the CTO, you will own the technical direction, architecture and engineering standards of the platform without direct line‑management responsibility. You will work closely with Product, Data, Operations, DevOps and QA teams to deliver secure, resilient and scalable solutions while mentoring engineers through technical leadership and best practice.

Platform architecture

• Design, implement and review high‑quality Java and full‑stack solutions, APIs and integrations.
• Lead performance optimisation, scalability and resilience initiatives.
• Drive security best practices, vulnerability remediation and secure software development lifecycle (SDLC) practices.
• Work closely with Data, Operations, DevOps and QA teams to ensure architectural alignment and operational excellence.

Product roadmap

• Translate business and product requirements into robust technical solutions.
• Support engineering teams in the successful delivery of roadmap commitments.
• Facilitate collaboration across teams to remove technical blockers and mitigate delivery risks.
• Mentor and guide developers to improve capability, quality and delivery outcomes.

Engineering standards

• Conduct design and code reviews to ensure quality, maintainability and consistency.
• Author new development processes and continuously improve existing engineering practices.
• Promote secure, scalable and maintainable software design across all teams.
• Support and mentor team members to drive technical excellence and continuous improvement.

Production systems

• Lead root cause analysis and resolution of complex production issues.
• Drive improvements in system observability, monitoring and operational performance.
• Ensure applications are designed and operated to meet reliability, availability and performance targets.
• Partner with Operations, DevOps and QA teams to maintain production stability and service quality.
• Embed a culture of operational excellence, continuous improvement and proactive issue prevention.

Technologies you will be using

• Java 21 (LTS)
• Spring Framework 6 / Spring Boot 3.5
• Hibernate ORM 6.6+, JPA
• Apache Tomcat 11, IntelliJ IDEA
• AI Tooling (Claude, Codex, GitLab Duo, etc.)
• REST APIs, OpenAPI, Microservices, Event‑driven architecture (RabbitMQ)
• Containers, Docker, AWS, Linux
• CI/CD with GitLab Pipelines & Jenkins
• Observability: logging, metrics and monitoring
• MySQL, Apache Solr
• Front‑end UI (e.g. Angular)

Person Specification

• Strategic and systems‑thinking mindset
• Excellent communication and stakeholder management skills
• Ability to influence through technical leadership rather than line management
• Proactive, pragmatic and outcome‑focused
• Strong mentoring and collaborative working style
• High standards of engineering excellence and continuous improvement
• Trusted technical advisor
• Excellent attention to detail

Education, Experience & Skills

• Degree in Computer Science (or equivalent experience)
• Extensive Java software engineering experience with significant experience in technical leadership
• Expert knowledge of Java, JVM performance and modern language features
• Deep experience with Spring Boot, Hibernate/JPA and enterprise application architecture
• Strong understanding of distributed systems, scalability, resilience and performance tuning
• Experience with cloud‑native applications, Docker, Kubernetes and CI/CD
• Strong knowledge of application security, OWASP principles and secure development practices
• Knowledge of a modern front‑end node‑based framework

Other Information

• Permanent role – 37.5 hours per week. Monday to Friday 9am‑5:30pm.
• 3‑month probationary period.