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-codeGuide and mentor engineers, promoting best practice, clean coding, and agile deliveryCollaborate with stakeholders and clients to shape technical direction and ensure robust, user-focused solutionsContribute across the full software development lifecycle, from discovery to production supportEssential Skills & Experience:Deep expertise in Java, with strong full-stack engineering skillsProven experience leading teams or projects at a senior/principal levelStrong knowledge of system architecture, cloud solutions, and API designFamiliarity with DevOps tools and automation (CI/CD, containers, IaC)Track record of delivering secure, production-grade systems in agile teamsExcellent stakeholder engagement, influencing, and communication skillsDesirable:Background in secure or classified environmentsKnowledge of ITSM or systems within the government/defence sectorExperience balancing technical leadership with hands-on developmentWhats in It for You:Flexible working 37.5 hrs/week with remote and hybrid optionsLearning & development budget for training, certifications, and conferencesPrivate healthcare & matched pension schemeMonthly socials and quarterly company meetupsClear career progression into leadership roles in a high-impact sectorDiversity & 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.Salary: £55,000 - £70,000 per annum #J-18808-Ljbffr