Senior Java Developer

Location:
Dublin or Manchester (Hybrid)
Reports to:
Engineering Manager
Overview
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.
Responsibilities
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
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
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
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 or follow on LinkedIn @Datalex.
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