Java Developer

Addition Solutions LTD; Cheltenham; On-site; GBP 70,000 - 110,000; Full time

Job summary

Addition Solutions LTD is seeking a seasoned Java backend engineer to design secure, high-performance services for national security projects. You will build scalable microservices and REST APIs, integrate with analytics platforms, and ensure secure coding practices.

The role involves collaborating with stakeholders, contributing to architecture, and maintaining observability across production systems. The position emphasizes modern backend architectures, DevSecOps practices, and strong

Qualifications

• Expert Java (11+) with Spring Boot.
• Strong backend design and OOP skills.
• Experience building microservices and REST APIs.
• Experience with Docker, Kubernetes, CI/CD and automated tests.
• Active DV security clearance (essential).

Responsibilities

• Designing and developing secure Java-based backend services for mission-critical systems.
• Building scalable microservices and RESTful APIs to support intelligence and data platforms.
• Developing high-performance distributed applications capable of handling large, complex datasets.
• Integrating backend systems with streaming, analytics, and AI/ML-enabled platforms.
• Applying secure coding principles to meet strict performance, resilience, and security standards.
• Contributing to architectural decisions, code reviews, and continuous improvement initiatives.
• Implementing observability, logging, and monitoring to support production environments.
• Collaborating with stakeholders to translate requirements into robust technical solutions.

Skills

Java (11+)

Backend design

Distributed systems

OOP & design

Stakeholder collaboration

Security clearance

Tools

Docker

Kubernetes

CI/CD

Automated testing

Observability tools

Job description

Role Overview

Location: Gloucester, London or Manchester (up to 80% onsite) Package: Competitive salary + benefits Industry: National Security / Software Engineering

What You'll Be Doing

• Designing and developing secure Java-based backend services for mission-critical systems
• Building scalable microservices and RESTful APIs to support intelligence and data platforms
• Developing high-performance distributed applications capable of handling large, complex datasets
• Integrating backend systems with streaming, analytics, and AI/ML-enabled platforms
• Applying secure coding principles to meet strict performance, resilience, and security standards
• Contributing to architectural decisions, code reviews, and continuous improvement initiatives
• Implementing observability, logging, and monitoring to support production environments
• Collaborating with stakeholders to translate requirements into robust technical solutions

Main Skills Needed

• Strong commercial experience with Java (11+) and frameworks such as Spring Boot
• Solid understanding of object-oriented programming and backend system design
• Experience building microservices and RESTful APIs in distributed environments
• Background in scalable, high-performance systems, ideally in data-intensive domains
• Familiarity with DevSecOps practices including Docker, Kubernetes, CI/CD pipelines and automated testing
• Understanding of system observability and production support tooling
• Ability to work closely with stakeholders to define and deliver technical solutions
• Active DV security clearance (essential)

What's in It for You

• Work on highly secure, nationally significant systems with real-world impact
• Exposure to complex, large-scale backend engineering challenges
• Opportunity to work with modern architectures including microservices and cloud-native tooling
• Strong emphasis on engineering quality, security, and continuous improvement
• Collaborative, technically strong teams operating in mission-focused environments
• Long-term career development within a highly specialised and growing sector

We are an equal opportunity employer and value diversity at our company. We do not discriminate on the basis of race, religion, colour, national origin, gender, sexual orientation, age, marital status, veteran status, or disability status.