Lead/Principle Software Engineer

Sanderson Government & Defence; Cheltenham; On-site; GBP 110,000 - 150,000; Full time

Job summary

Sanderson Government & Defence is seeking an experienced Lead/Principal Software Engineer to join a fast‑paced, secure development team delivering mission‑critical Government and Defence solutions in the UK.

You will design and build scalable backend platforms, lead technical decisions, and mentor engineers across cross‑functional squads while operating within Agile DevSecOps, cloud-native environments and modern CI/CD pipelines to ensure robust, secure software delivery.

Qualifications

• 5+ years of commercial software engineering experience delivering production-grade solutions in complex environments.
• Strong experience developing Java applications.
• Experience with Kotlin or Scala on the JVM.
• Experience with Kafka or similar messaging/event-streaming.
• Experience integrating with PostgreSQL, Redis, and S3/Object Storage.
• Deep understanding of microservices, distributed systems and modern software design patterns.
• Experience with Big Data and data-intensive applications.
• Experience working in Agile DevSecOps environments.
• Knowledge of Zero Trust Architecture principles.
• Strong CI/CD, automated deployments and modern software delivery practices.
• Commitment to clean code, reviews, and high-quality documentation.
• Experience using GitHub, GitLab and Atlassian tools.

Responsibilities

• Design, develop, deploy and enhance backend platforms and services for mission-critical programmes.
• Deliver secure, scalable software meeting functional and non-functional requirements.
• Participate in Agile ceremonies and continuous improvements.
• Collaborate with engineers, architects and product stakeholders.
• Own services from design through production support and ongoing reliability.
• Build and optimise CI/CD pipelines and deployment processes.
• Contribute to engineering standards and QA practices across the lifecycle.
• Support knowledge sharing and a collaborative engineering culture.
• Troubleshoot and resolve production issues when required.

Skills

5+ years experience

Java

Kotlin/Scala

Kafka

PostgreSQL

Redis

S3/Object Storage

Microservices

Big Data

DevSecOps

Zero Trust

CI/CD

GitHub/GitLab

Atlassian

Problem Solving

Tools

Docker

Kubernetes

AWS

Azure

GitHub

GitLab

Atlassian Suite

Job description

Lead/Principle Software Engineer

Clearance Required: Active SC Clearance (Mandatory)

The Opportunity

We're looking for an experienced Software Engineer to join a high-performing team delivering secure, mission-critical solutions for Defence, National Security, and Government customers.

This role offers the opportunity to design and develop modern backend platforms and services that support some of the UK's most complex and secure technology programmes. Working within Agile, cloud-native environments, you'll leverage cutting-edge commercial and open-source technologies to build scalable, resilient, and high-performing systems across both public and private cloud infrastructure.

You'll play a key role in the full software development lifecycle, from solution design through to deployment and operational support, while collaborating with multidisciplinary teams to deliver innovative solutions that make a real-world impact.

Please note: Active SC Clearance is an essential requirement for this position. Due to the nature of the work, candidates must already hold current and active SC Clearance. Unfortunately, sponsorship or clearance applications cannot be supported for this role.

Key Responsibilities

• Design, develop, deploy, and enhance backend platforms, applications, and services that support mission-critical programmes.
• Deliver secure, scalable, and maintainable software solutions that meet both functional and non-functional business requirements.
• Participate in Agile ceremonies, including sprint planning, story refinement, estimation, and retrospectives.
• Deliver incremental software releases and continuous improvements through modern Agile delivery practices.
• Collaborate closely with engineers, architects, and product stakeholders across cross-functional teams.
• Take ownership of the services and applications your team delivers, ensuring ongoing reliability, performance, and supportability.
• Build, maintain, and optimise Continuous Integration and Continuous Deployment (CI/CD) pipelines.
• Contribute to engineering standards, best practices, and quality assurance processes across the development lifecycle.
• Support knowledge sharing and foster a collaborative engineering culture.
• Assist in troubleshooting, root cause analysis, and resolution of production issues when required.

Skills & Experience

Essential

• 5+ years' commercial software engineering experience delivering production-grade solutions within complex environments.
• Strong commercial experience developing applications using Java.
• Experience working with other JVM-based technologies such as Kotlin and/or Scala.
• Experience with messaging and event-streaming technologies such as Kafka.
• Strong experience integrating with backend services including PostgreSQL, Redis, and S3/Object Storage solutions.
• Deep understanding of microservices architecture, distributed systems, and modern software design patterns.
• Experience working with Big Data technologies and data-intensive applications.
• Experience operating within Agile DevSecOps environments.
• Knowledge and application of Zero Trust Architecture principles.
• Strong experience with CI/CD pipelines, automated deployments, and modern software delivery practices.
• Commitment to clean coding standards, code reviews, defensive programming, and high-quality technical documentation.
• Experience using source control and collaboration platforms including GitHub, GitLab, and the Atlassian Suite.
• Strong problem-solving skills with the ability to design and implement scalable technical solutions.

Desirable

• Experience working within AWS, Azure, or other cloud-native environments.
• Knowledge of containerisation and orchestration technologies such as Docker and Kubernetes.
• Experience supporting highly regulated industries such as Defence, National Security, Government, or Critical Infrastructure.
• Exposure to high-volume, real-time, or event-driven architectures.
• Relevant industry certifications across software engineering, cloud, or security disciplines.

What You'll Bring

• Strong backend engineering expertise with a passion for developing secure, scalable, and reliable systems.
• The ability to lead technical discussions and influence engineering decisions across teams.
• A thorough understanding of modern software engineering principles and best practices.
• A proactive approach to ownership, taking responsibility for services from initial design through to production support.
• A collaborative mindset with the ability to work effectively across multidisciplinary teams.
• Excellent communication skills and a commitment to continuous learning and technical improvement.
• The ability to thrive in challenging and highly secure technical environments.

Testing & Quality

Essential Experience

• Strong advocate of Test-Driven Development (TDD) and quality-first engineering practices.
• Experience using modern testing frameworks and automated testing tools.
• Proven ability to build scalable, secure, maintainable, and well-tested software solutions.
• Commitment to continuous improvement, engineering excellence, and delivering robust code into production.

Security Clearance

Mandatory Requirement

Candidates must hold current and active SC (Security Check) Clearance at the time of application.

Applications from candidates who are eligible for clearance, willing to undergo clearance, or whose clearance has expired cannot be considered for this position.

This is an outstanding opportunity to work on some of the UK's most complex and impactful technology programmes, developing secure cloud-native platforms and services that directly support critical national outcomes while working alongside highly skilled software engineers, architects, and technology specialists

Reasonable Adjustments:

Respect and equality are core values to us. We are proud of the diverse and inclusive community we have built, and we welcome applications from people of all backgrounds and perspectives. Our success is driven by our people, united by the spirit of partnership to deliver the best resourcing solutions for our clients.

If you need any help or adjustments during the recruitment process for any reason, please let us know when you apply or talk to the recruiters directly so we can support you.