Senior Java Engineer
This position is listed on behalf of a partner company, who manages all applications and next steps. Our partner is looking for a Senior Java Engineer based in United Kingdom.
As a Senior Java Engineer, you will take technical ownership of reliable, scalable payment platforms serving demanding financial and fintech environments. You will design and build secure, high-performance systems that process transactions at scale, owning features from architecture through production. The role combines hands-on software engineering with technical leadership, mentoring, and architectural decision-making. You will work closely with Product, Architecture, DevOps, and other technical stakeholders to translate complex business requirements into robust solutions. You will also contribute to application reliability, security, observability, and continuous delivery practices. This is an international, distributed engineering environment where precision, ownership, collaboration, and curiosity are highly valued.
Accountabilities
Design, develop, and maintain enterprise-grade applications using Java and Spring Boot, taking ownership of features throughout their full lifecycle from design to production.
Lead the technical design of significant application components, including service boundaries, data models, integration patterns, and non-functional requirements.
Collaborate with Product Managers, Solution Architects, DevOps Engineers, and other stakeholders to translate business requirements into scalable technical solutions and challenge requirements when technical trade-offs need to be addressed.
Own application reliability, performance, security, and compliance with relevant security and regulatory standards.
Design and maintain integrations with external systems, APIs, and third-party service providers.
Write clean, efficient, maintainable, and testable code while promoting sound engineering practices and established design principles.
Improve CI/CD pipelines, automated testing, observability, deployment processes, and overall engineering efficiency.
Lead code reviews, mentor junior and mid-level engineers, and serve as a technical escalation point for complex engineering challenges.
Participate in production incident response, conduct root-cause analysis, and implement durable solutions to prevent recurring issues.
Contribute to technical innovation and stay informed about emerging technologies and trends across software engineering and the payments industry.
5+ years of professional Java development experience, with a proven track record of owning complex, production-grade systems.
Strong expertise in modern Java, particularly Java 21/25 LTS, and Spring Boot 4 / Spring Framework 7 for developing RESTful and event-driven microservices.
Solid experience with Apache Kafka and asynchronous processing, including concepts such as idempotency and exactly-once semantics.
Strong knowledge of relational databases such as PostgreSQL and MySQL, along with ORM technologies including Hibernate and JPA.
Proven API design capabilities using REST and OpenAPI, with a strong understanding of integration patterns and best practices.
Hands-on experience with AWS, Docker, Kubernetes, and modern CI/CD tooling, including Maven or Gradle, GitHub Actions, Helm, and Terraform.
Strong testing practices using technologies such as JUnit 5, Mockito, and Testcontainers.
Practical experience with production observability and monitoring tools such as OpenTelemetry, Prometheus, and Grafana.
Working knowledge of security concepts including encryption, OAuth2/OIDC, JWT, mutual TLS, HSM integration, and tokenization.
Practical experience using AI coding assistants and LLMs as part of the software development workflow, combined with the judgment required to validate and refine AI-generated output.
Experience mentoring engineers, leading code reviews, and collaborating effectively within distributed and international teams.
Strong attention to precision, reliability, security, and code quality.
Adaptability and curiosity, with the ability to move across technical domains and business problem spaces while maintaining delivery momentum.
Strong communication and collaboration skills when working with diverse technical and business stakeholders.
A high level of ownership and accountability, with a proactive approach to delivering production-ready solutions.
A technical leadership mindset focused on improving engineering standards across the wider team.
Work on high-impact technology solutions within the payments and fintech sector.
Take significant technical ownership over scalable, secure, and business-critical platforms.
Work remotely from Germany within a distributed European environment.
Collaborate with experienced technical and business professionals across different teams and geographies.
Opportunity to influence architecture, engineering standards, development practices, and technical direction.
Continuous exposure to modern technologies across cloud infrastructure, distributed systems, security, observability, and payment technology.
Opportunities to mentor engineers and expand your technical leadership responsibilities.
A collaborative environment that values precision, reliability, innovation, ownership, and continuous learning.
Work on complex engineering challenges where scalability, security, and performance are central to the product experience.
Full-time employment with an experienced/senior-level scope.