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Principal Software Engineer in Belfast

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Job Description

Principal Java Engineer


Java | Kotlin | Cloud

At a glance

  • Principal level backend role with architectural ownership
  • Java and Kotlin microservices in a cloud environment
  • Hybrid working in Belfast
  • Salary up to £80k plus bonus


The role

As a Principal Java Engineer, you will provide technical leadership across a critical product area, shaping architecture, guiding engineering standards and influencing how scalable backend systems are designed and delivered.

You will work closely with Senior, Staff and Principal Engineers across Belfast and the wider global engineering organisation, contributing to large scale distributed systems while acting as a technical authority within the team.

This role offers a strong mix of hands-on development, architectural decision making and mentorship.


What you will be doing

  • Owning technical direction and architecture for key backend services
  • Designing, building and evolving scalable Java and Kotlin microservices
  • Driving best practices around TDD, BDD and clean code
  • Leading code reviews and setting high engineering standards
  • Decomposing complex monolithic systems into modern distributed architectures
  • Partnering with product, platform and engineering leadership on technical strategy
  • Owning production systems including reliability, monitoring and on-call standards
  • Identifying and addressing technical debt with a long term mindset
  • Mentoring Senior and mid-level engineers across the team
  • Contributing to continuous improvement of engineering processes and tooling


What you’ll need:

  • 8+ years’ experience in backend software engineering
  • Strong commercial experience using Java, with Kotlin exposure a plus
  • Proven experience designing and building scalable microservices
  • Strong background in Cloud architectures
  • Extensive experience designing and building RESTful APIs
  • Deep understanding of SOLID principles and software design patterns
  • Strong experience with relational databases such as MySQL
  • Ability to influence architecture and technical decisions at team level and above
  • Excellent problem solving and communication skills


What’s on offer

  • Competitive salary up to £80k plus bonus
  • Generous benefits package
  • Hybrid working with a modern Belfast office
  • Principal level role with genuine technical influence and ownership

For more information on this opportunity, connect with Neill Ferguson on LinkedIn or submit your CV via the link below.

If you are interested in applying for this job please press the Apply Button and follow the application process. Energy Jobline wishes you the very best of luck in your next career move.

Principal Software Engineer in Belfast

Belfast, UK
Full time

Published on 01/26/2026

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