Senior Java Developer bei Datalex

Senior Java Developer – Spring Boot, REST API, Kubernetes/AWS 

Location: Dublin or Manchester (Hybrid) 

Department: Engineering 

Reports to: Engineering Manager 

About the Role 

We are seeking a highly skilled Senior Java Developer to lead the modernization of our legacy monolithic architecture by decomposing SOAP-based services into stateless RESTful microservices. You will be responsible for transitioning our legacy SOAP-based services to RESTful, scalable microservices using Spring Boot, deployed in AWS via Docker and Kubernetes (or ECS). This is a high-impact role where your expertise will directly influence system scalability, performance, and developer experience. 

Key Responsibilities 

API Development & Architecture 

•  Apply domain-driven design and stateless principles to migrate business functionality from the monolith to a modern architecture 

• Lead the decomposition of tightly coupled SOAP services into independently deployable microservices 

• Design and implement scalable, stateless REST APIs using Spring Boot and SwaggerHub 

• Lead the transformation from SOAP/XML to REST/JSON for internal and external APIs 

• Serve as the front controller for managing requests and orchestrating backend service flows 

Microservices & Cloud Deployment 

• Develop and deploy containerized microservices using Docker and Kubernetes, or AWS ECS 

• Implement cloud-native architecture patterns for high availability, fault tolerance, and scalability in AWS 

• Integrate with API Gateway, Lambda, and CloudFormation or other IaC tools for provisioning infrastructure 

Testing & Quality 

• Write comprehensive integration, unit, and API tests using JUnit, Mockito, Postman, etc. 

• Debug REST-to-SOAP interactions to ensure seamless migration and data integrity 

• Champion CI/CD and test automation practices across the team 

Performance, Caching & DevOps 

• Optimize performance with caching solutions (e.g., Redis, Memcached) 

• Maintain stateless service architecture principles 

• Contribute to observability with Prometheus, Grafana, and ELK Stack 

Collaboration & Leadership 

• Collaborate closely with product, QA, DevOps, and platform teams 

•  Mentor junior engineers and support technical decision-making across sprints 

• • Advocate for engineering excellence, TDD, and best practices in software delivery 

Required Skills & Experience 

• Experience leading end-to-end migration projects from SOAP-based systems to scalable, domain-aligned microservices 

• Proven experience decomposing monolithic applications and rebuilding them as RESTful microservices 

• 7+ years in Java development with strong expertise in Spring Boot 

• Strong knowledge of REST architecture principles and best practices 

• Proven experience designing and building REST APIs at scale 

• Deep understanding of SOAP-to-REST transformations 

• Hands-on with Docker and either Kubernetes or AWS ECS (Elastic Container Service) 

• Proficiency in one or more Infrastructure as Code (IaC) frameworks: Terraform, AWS CloudFormation, or AWS CDK 

• Strong database knowledge: PostgreSQL, MySQL, MongoDB, Redis 

• Proficient with CI/CD tools (e.g., Jenkins, GitLab CI, AWS CodePipeline) 

• Strong testing discipline with tools like JUnit, Mockito, Postman, or Karate 

• Experience with OAuth2, JWT, OpenID Connect 

• Familiarity with Java 8+ and awareness of Java 11/17 improvements 

Preferred Skills 

• Experience with API Gateways (AWS API Gateway, Kong) 

• Knowledge of Kafka, RabbitMQ 

• Experience with serverless architectures (e.g., AWS Lambda) 

• Broader experience with Infrastructure as Code tooling and best practices 

About Datalex 

Datalex's purpose is to transform airline retail. Datalex is a market leader in airline retail technology, offering unique products that enable airlines to drive revenue and profit as digital retailers. Datalex has a strong track record of delivering digital retail transformation for progressive airline brands worldwide, including Aer Lingus, easyJet, JetBlue Airways, Air China, Edelweiss, Air Transat, and Air Macau. The Group is headquartered in Dublin, Ireland, and maintains offices across Europe, the USA and China. In 2024, Datalex was awarded the 'Great Place to Work and 'Best Workplaces in Tech' certifications. Datalex plc is a publicly listed company, on Euronext Growth, Dublin. Learn more at www.datalex.com or follow on LinkedIn @Datalex.