Principal Java Engineer

Group GTI; Wallingford; Hybrid; GBP 110,000 - 160,000; Full time

Job summary

Group GTI in Wallingford, UK, is seeking a Principal Java Engineer to provide technical leadership for their core SaaS platform. You will own architecture, set engineering standards and mentor teams, collaborating with Product, Data, Ops and QA to deliver secure, scalable solutions.

The role emphasizes driving performance, security, and operational excellence while shaping the technology roadmap with CTO oversight. Hybrid working in the UK is offered.

Qualifications

• Degree in Computer Science or equivalent experience.
• Extensive Java software engineering experience with significant leadership.
• Expert knowledge of Java, JVM performance and modern language features.
• Deep experience with Spring Boot, Hibernate/JPA and enterprise 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 secure development practices.
• Knowledge of a modern front-end node-based framework.

Responsibilities

• Own the application architecture and technical direction across products and services.
• Design, implement and review high-quality Java and full-stack solutions, APIs and integrations.
• Lead performance, scalability and resilience initiatives.
• Drive security best practices and secure SDLC.
• Mentor engineers and ensure architectural alignment across teams.
• Provide technical leadership across multiple Agile teams and translate requirements into robust solutions.
• Support roadmap delivery and remove technical blockers to improve delivery outcomes.
• Define and champion engineering standards and development practices.
• Lead root cause analysis and drive observability and operational excellence.

Skills

Java

Technical leadership

Distributed systems

Security

Education

Degree in Computer Science

Tools

Docker

Kubernetes

GitLab

Jenkins

Angular

MySQL

Apache Solr

OpenAPI

Spring Boot

Hibernate/JPA

Tomcat

AWS

Job description

Principal Java Engineer

Department: Tech

Employment Type: Permanent - Full Time

Location: Wallingford, UK - Hybrid

Description

Mission: 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.

Outcomes

Platform architecture is scalable, resilient, secure and supports current and future business needs

• Own the application architecture and technical direction across multiple products and services.
• 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 is delivered successfully through strong technical leadership and effective engineering execution

• Provide technical leadership across multiple Agile development teams.
• 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, architecture principles and best practices are consistently applied across development teams

• Define, maintain and champion engineering standards, architectural principles and development best practices.
• 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 are reliable, observable and operationally excellent

• 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

Work Experience, Knowledge & 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.

Candidates applying for roles at GTI will be subject to background screening. You can find out more about our background screening and the recruitment of ex-offenders by reading our policies.

If you would like to speak to a member of our team to find out more information about this vacancy or you have any questions, please get in touch - [e-mail].