Principal Java Developer

NPAworldwide; Oxford; Hybrid; GBP 80,000 - 100,000; Full time

Job summary

A mission-led consultancy in the United Kingdom is seeking an experienced Principal Software Engineer to lead the design and development of secure software solutions. This senior role requires deep expertise in Java and knowledge of systems architecture. Ideal candidates will thrive in Agile environments, promoting best practices while contributing to the codebase. The position offers flexible working, a learning budget, and opportunities for career progression in the UK Government and Defence sectors.

Benefits

Flexible working hours

Learning & development budget

Private healthcare

Matched pension scheme

Monthly socials

Qualifications

• Deep expertise in Java, with strong full-stack engineering skills.
• Proven experience leading teams or projects at a senior/principal level.
• Strong knowledge of system architecture, cloud solutions, and API design.

Responsibilities

• Lead the design, development, and testing of secure systems using Java.
• Architect and maintain APIs and cloud-native solutions.
• Drive adoption of DevOps practices and mentor engineers.

Skills

Java

System architecture

API design

DevOps practices

Stakeholder engagement

Job description

Our client, a mission‑led consultancy , is looking for an experienced Principal Software Engineer (Java) to join their growing team. They deliver secure, modern software solutions to the UK Government and Defence sectors, enabling clients to build scalable systems and progressive web applications that drive real impact.

This is a senior‑level opportunity for a hands‑on engineer who enjoys leading by example , thrives in agile environments , and is passionate about shaping engineering best practice while still contributing to the codebase.

Key Responsibilities

• Lead the design, development, and testing of secure, scalable systems using Java with modern front‑end frameworks (e.g., React)
• Architect and maintain APIs, data pipelines, and cloud‑native solutions (AWS, Azure, private cloud)
• Drive adoption of DevOps practices – CI / CD, containers, infrastructure‑as‑code
• Guide and mentor engineers, promoting best practice, clean coding, and agile delivery
• Collaborate with stakeholders and clients to shape technical direction and ensure robust, user‑focused solutions
• Contribute across the full software development lifecycle , from discovery to production support

Essential Skills & Experience

• Deep expertise in Java , with strong full‑stack engineering skills
• Proven experience leading teams or projects at a senior / principal level
• Strong knowledge of system architecture , cloud solutions, and API design
• Familiarity with DevOps tools and automation (CI / CD, containers, IaC)
• Track record of delivering secure, production‑grade systems in agile teams
• Excellent stakeholder engagement, influencing, and communication skills

Desirable

• Background in secure or classified environments
• Knowledge of ITSM or systems within the government / defence sector
• Experience balancing technical leadership with hands‑on development

What’s in It for You

• Flexible working – 37.5 hrs / week with remote and hybrid options
• Learning & development budget for training, certifications, and conferences
• Private healthcare & matched pension scheme
• Monthly socials and quarterly company meetups
• Clear career progression into leadership roles in a high‑impact sector

Diversity & Inclusion

Our client is an equal opportunities employer and a Disability Confident organisation , committed to fostering a workplace where diverse perspectives are celebrated and everyone can thrive.

How to Apply

If you’re an experienced Principal Software Engineer with expertise in Java , and you’re excited to help deliver solutions that truly matter, we’d love to hear from you.