Senior Java Developer

Overview Location: Dublin or Manchester (Hybrid)
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

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 www.datalex.com or follow on LinkedIn @Datalex.

Do you have eligibility to work and reside in the country of employment? *

Are you currently based in the country of employment?

How many years experience do you have? *

We currently operate in a hybrid model. Would you be willing to be onsite 2 days per week? * Yes No

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