Senior Fullstack Developer — Java or Kotlin, React and TypeScript

Salary: £51,000 - 91,000 per year

Requirements:

• Strong commercial experience developing server-side applications with Kotlin or modern Java, ideally Java 17 or later.
• Good knowledge of the JVM ecosystem and common backend development practices.
• Experience designing, building and operating APIs and distributed services.
• Understanding of service reliability, maintainability, performance and security.
• Proven experience writing effective automated tests.
• Practical experience with relational databases.
• Experience with modern frontend development, ideally using React and TypeScript.
• Familiarity with CI/CD practices and supporting software in production.
• Experience working collaboratively in an agile, product-focused engineering team.
• Curiosity about AI-augmented engineering and a willingness to develop new ways of working.
• A thoughtful approach to code quality, technical trade-offs and continuous improvement.
• Equivalent experience with comparable technologies will be considered.

Responsibilities:

• Build and maintain reliable JVM-based services using Kotlin or modern Java.
• Design and develop well-structured APIs and integrations.
• Build reusable services, APIs and components that enable other teams to deliver consistently and reduce duplication.
• Contribute to API design standards, documentation and versioning across services.
• Deliver complete end-to-end features by connecting backend services and data models with responsive web interfaces.
• Use appropriate test-first and test-informed practices to create effective automated tests.
• Experiment with AI-assisted engineering tools where they provide clear value, such as exploring solutions, improving tests, documenting systems or investigating issues.
• Validate AI-assisted outputs for correctness, security, maintainability and suitability before they are used.
• Contribute to event-driven workflows and asynchronous processing using suitable messaging or streaming technologies.
• Participate in technical discovery, spikes, architecture discussions and peer code reviews.
• Improve build, test and deployment pipelines to support safe and efficient delivery.
• Embed structured logging, metrics and distributed tracing to make services easier to operate and troubleshoot.
• Consider the operational, security and governance implications of engineering decisions, particularly in complex or regulated environments.
• Identify and address technical debt, performance issues and reliability risks.
• Share knowledge, support collective code ownership and contribute to a collaborative, low-ego team culture.

Technologies:

• AI
• API
• Backend
• CI/CD
• Frontend
• Fullstack
• Support
• JVM
• Java
• Kotlin
• React
• Security
• TypeScript
• Web
• AWS
• Azure
• BPMN
• Cloud
• Docker
• Excel
• GCP
• GraphQL
• JavaScript
• Ktor
• Kubernetes
• NoSQL
• Quarkus
• Spring
• Spring Boot

More:

Founded in Switzerland in 1968, we are owned by our partners and located across Europe and Asia. We are a global transformation partner with engineering and innovation in our DNA, trusted to help clients envision and build their businesses for the future. Our multidisciplinary teams specialise in tech strategy and business innovation, digital solutions and applications, and device and systems engineering, with deep experience in complex, regulated spaces including health and finance. This senior fullstack role is backend-led and hands-on, working in a cross-functional engineering squad alongside product, design and delivery colleagues. We offer the chance to work on a global scale, shape our exciting journey, and contribute in an increasingly AI-augmented engineering environment. The role is based in London or Manchester, is full time, and may include working on-site with clients and occasional travel depending on project needs. We welcome people from all backgrounds.

last updated 35 week of 2026