Senior Java Developer


CastileLa Mancha, Castilla-La Mancha, España UST España & Latam Jornada completa

We are still looking for the very Top Talent…and we would be delighted if you were to join our team

More in details, UST is a multinational company based in North America, certified as a Top Employer and Great Place to Work company with over 35,000 employees all over the world and presence in more than 35 countries . We are leaders in digital technology services, and we provide large-scale technological solutions to big companies.

What we look for?

We are looking for a Java Developer to join a highly innovative team working within a microservice-based cloud environment in the utility technology sector. You will play a key role in designing, developing, and supporting secure, scalable, and maintainable Java services, APIs, and integrations that connect critical business systems and internal tools.

⚙ Key Responsibilities:

  • Design and implement Java services, REST APIs, integration adapters, and extension components using Java and the Spring ecosystem.
  • Translate business requirements, user stories, and interface specifications into clean, maintainable, and scalable code.
  • Develop RESTful APIs with proper validation, versioning, pagination, security, and error-handling mechanisms.
  • Implement reliable event-driven and asynchronous integrations, ensuring resiliency through retry, timeout, correlation, idempotency, and dead-letter patterns.
  • Build and optimize persistence layers using Hibernate/JPA and SQL best practices.
  • Integrate microservices and internal tools with CRM, finance, payment, analytics, web, and mobile platforms.
  • Create and maintain unit, integration, component, and contract tests to ensure high-quality software delivery.
  • Participate in code reviews, technical design sessions, backlog refinement, and secure development practices.
  • Troubleshoot production incidents using logs, metrics, traces, and database analysis, providing sustainable root-cause solutions.
  • Support CI/CD pipelines, automated quality controls, deployment processes, and cloud-native engineering practices.
  • Contribute to technical documentation, operational procedures, and service supportability improvements.
  • Ensure solutions meet performance, reliability, scalability, and security standards.

Mandatory Requirements:

  • Strong professional experience developing enterprise applications with Java .
  • Hands-on experience with Spring Framework and Spring Boot .
  • Solid knowledge of Hibernate/JPA , relational databases, and SQL optimization .
  • Experience designing and consuming REST APIs and working with OpenAPI/Swagger specifications.
  • Experience with event-driven architectures , asynchronous messaging, or distributed systems.
  • Strong testing experience using JUnit , Mockito , and integration/contract testing frameworks.
  • Experience working with Git , Maven/Gradle , CI/CD pipelines, and code review practices.
  • Understanding of secure coding principles, authentication, authorization, observability, logging, and monitoring.
  • Strong analytical, problem-solving, and debugging skills.
  • Excellent communication skills and fluent English.

Nice to have:

  • Experience in utility, customer information, billing, payment, or energy-sector platforms.
  • Knowledge of platforms such as SAP Utilities , Oracle Utilities , Kraken Technologies , or Hansen .

Experience with AWS , including:

  • API Gateway
  • Lambda
  • Fargate
  • EventBridge
  • SQS/SNS
  • Aurora
  • CloudWatch
  • IAM
  • Secrets Manager
  • Experience with containers, infrastructure-as-code, and cloud-native deployment patterns.
  • Knowledge of distributed tracing, performance testing, and production support for high-volume systems.
  • Understanding of customer, metering, usage, tariff, billing, payment, and debt-management processes within utilities.

What can we offer?

  • ✈️ 23 days of Annual Leave plus the 24th and 31st of December as discretionary days
  • ❤️ Numerous benefits (Health Care Plan, Internet Connectivity, Life and Accident Insurances).
  • Retribución Flexible Program: (Meals, Kindergarten, Transport, Online English Lessons, Health Care Plan…)
  • Free access to several training platforms.
  • Professional stability and career plans.
  • UST also compensates referrals, from which you could benefit when you refer professionals.
  • The option to pick between 12 or 14 payments along the year.
  • Real Work-Life Balance measures (flexibility, WFH or remote work policy, compacted hours during summertime…).
  • UST Club Platform discounts and gym access discounts