Senior Fullstack Developer - Java & React

Senior Fullstack Developer - Java & React

Zühlke Group

London or Manchester, United Kingdom

As a Senior Full stack Developer, you will be a hands-on member of a high-performing engineering squad, building and operating business-critical digital services.

This is a backend-led full-stack role. You will use Kotlin or modern Java, ideally Java 17 or later, together with the wider JVM ecosystem, to develop reliable services and APIs. You will also contribute to modern web interfaces using technologies such as React and TypeScript.

You will work in an increasingly AI-augmented engineering environment. We are looking for people who are curious about AI-augmented engineering and willing to experiment with tools that improve software delivery. You will not be expected to use AI tools every day, but you should be open to applying them where they provide clear value, while validating outputs for correctness, security and maintainability.

Working closely with product managers, designers, engineers, and architects, you will turn product requirements into well-structured, maintainable, production-ready solutions. You will contribute throughout the delivery lifecycle—from technical discovery and implementation through to deployment, production support and continuous improvement.

You will take ownership of significant features and services, contribute to technical decisions, support other engineers and help maintain high standards of engineering quality.

How you will make an impact

• Build and maintain reliable JVM-based services using Kotlin or modern Java.
• Design and develop APIs and integrations following industry standards.
• Contribute to API design standards and documentation.
• Deliver complete end-to-end features by connecting backend services and data 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 using them.
• Contribute to event-driven workflows and asynchronous processing.
• 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.

What's important to us

• 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.
• 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.

Desirable experience

• Practical experience using AI-assisted development or productivity tools in a software engineering context.
• Familiarity with asynchronous & event-driven architectures.
• Experience with frameworks such as Spring Boot, Quarkus, Micronaut or Ktor.
• Cloud platforms such as AWS, Azure or GCP.
• Developing with containers
• Understanding the difference between relational, NoSQL and other persistence technologies.
• Experience building shared platforms, common services or greenfield technical foundations.
• Building APIs adhering to design principles such as RESTful API design
• Building observable systems
• Experience in regulated or financial-services environments.
• Exposure to payments, transaction processing or other business domains.
• Equivalent experience with comparable technologies will be considered.

What success looks like

In this role, you will:

• deliver valuable, production-ready features with the squad;
• build services and APIs that are reliable, reusable and easy for others to consume;
• improve the reliability, performance and operability of the services you work on;
• use emerging engineering tools thoughtfully and responsibly where they add value;
• contribute constructively to technical decisions, API standards and code reviews;
• help the team release software safely and efficiently; and
• support a culture of learning, collaboration and shared responsibility.