Senior Software Engineer – Java / DevSecOps / IAM

Senior Full Stack Software Engineer with strong Java, Spring Boot and React experience, alongside Kafka or RabbitMQ distributed systems expertise , is required to join an innovative, well-funded early-stage technology start-up developing next-generation SaaS solutions for the renewable energy sector.

Location is Cambridge, so being located close to Cambridge is an advantage, although remote work within the UK with occasional meet-ups is okay.

This is an opportunity for an experienced Full Stack Engineer to play a key role in designing, building and securing a scalable, cloud-native SaaS platform. You'll work across backend microservices, frontend applications and distributed systems, with a particular emphasis on secure software development, Identity & Access Management (IAM), DevSecOps and application security.

We're particularly interested in hands-on Full Stack Engineers with a strong Java backend bias , who are comfortable working across the stack and bring a good understanding of security patterns, authentication, authorisation and user management.

Key skills required for the Senior Full Stack Software Engineer

• Strong Java and Spring Boot experience , developing scalable, production-grade applications, APIs and microservices.
• Full Stack development experience , ideally with React, JavaScript/TypeScript and modern frontend frameworks.
• Kafka or distributed systems experience , including event-driven architectures, asynchronous messaging and scalable service communication.
• Good knowledge of Docker and Kubernetes , including containerisation and cloud-native application deployment.
• DevSecOps experience or strong understanding , including secure CI/CD pipelines, automated testing and security best practices throughout the development lifecycle.
• Identity & Access Management (IAM) knowledge, including authentication, authorisation, role-based access control (RBAC), user management and permissions.
• Understanding of application security patterns , secure API development, information security principles and secure-by-design architecture.
• Familiarity with OAuth 2.0, OpenID Connect (OIDC), JWT or similar authentication and authorisation technologies.
• Experience working with cloud infrastructure, ideally AWS, and designing resilient, maintainable SaaS applications.
• Strong software engineering fundamentals, automated testing and experience working in collaborative agile development teams.

Desirable experience:

• Identity management platforms such as Keycloak, Auth0 or AWS Cognito.
• React component libraries such as Material UI (MUI).
• Cloud security tooling, AWS IAM, OPA or IRSA.
• Kubernetes security, service meshes and microservice networking.
• Domain-Driven Design (DDD), platform engineering or infrastructure as code.
• Experience working in an early-stage technology business or SaaS product environment.

What you'll do as a Senior Full Stack Software Engineer

• Design, develop and maintain scalable Full Stack applications using Java, Spring Boot and React.
• Build secure backend microservices, REST APIs and distributed systems, using Kafka and event-driven architectures where appropriate.
• Develop intuitive, responsive frontend applications that integrate with complex backend services.
• Work with Docker, Kubernetes and cloud-native technologies to support reliable application delivery.
• Design and implement authentication, authorisation, IAM and user management functionality.
• Apply DevSecOps principles and secure development practices across frontend, backend and deployment processes.
• Collaborate with product stakeholders and engineering colleagues to translate requirements into high-quality technical solutions.
• Contribute to software architecture, automated testing, code reviews, pair programming and continuous improvement.
• Help shape engineering standards, security patterns and technical direction as the platform evolves.

Why this role?

• Modern Full Stack engineering: Work across Java, Spring Boot, React, Kafka, Docker, Kubernetes and cloud-native SaaS technologies.
• Security-focused development: Influence application security, IAM, user management and DevSecOps practices across the platform.
• Technical ownership: Play an important role in shaping the architecture and development of a new SaaS product.
• Growing technology start-up: Join a recently funded business with opportunities to influence technical decisions and product direction.
• Purpose-driven technology: Build software supporting the renewable energy industry and the transition towards a greener future.
• Collaborative culture: Work with experienced engineers who value technical excellence, autonomy, continuous learning and shared ownership.

This role would particularly suit a Senior Full Stack Engineer with a strong Java / Spring Boot backend bias, React frontend experience, Kafka or distributed systems knowledge, and familiarity with Docker, Kubernetes, DevSecOps and IAM.

Opus Resourcing acts as an employment agency with respect to permanent employment.

📩 Apply now or message us for more details. Referrals always welcome!

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