Senior Java Developer (AWS) - Remote en Spain, Madrid

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

More in details,USTis a multinational company based in North America, certified as aTop EmployerandGreat Place to Workcompany with over35,000 employeesall over the world and presence in more than35 countries. We are leaders in digital technology services, and we provide large-scale technological solutions to big companies.

We are looking for a Senior Java Developerto join a highly innovative team working within amicroservice-based cloud environmentin 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.

• 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.

• Strong professional experience developing enterprise applications withJava.
• Hands-on experience withSpring FrameworkandSpring Boot.
• Solid knowledge ofHibernate/JPA, relational databases, andSQL optimization.
• Experience designing and consumingREST APIsand working withOpenAPI/Swaggerspecifications.
• Experience withevent-driven architectures, asynchronous messaging, or distributed systems.
• Strong testing experience usingJUnit,Mockito, and integration/contract testing frameworks.
• Experience working withGit,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 andfluent English.

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

Experience withAWS, 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.

• 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.

If you would like to know more, do not hesitate to apply and we'll get in touch to fill you in details. UST is waiting for you!

AtUST, we are committed to equal opportunities in our selection processes and do not discriminate based on race, gender, disability, age, religion, sexual orientation, or nationality. We have a special commitment to Disability & Inclusion, so we are interested in hiring people with a disability certificate.