Senior Java Backend Engineer - Cloud & Microservices (Remote)

Ust España & Latam; Barcelona; Híbrido; EUR 90.000 - 120.000; Jornada completa

Ventajas ofrecidas por este puesto de trabajo

Annual leave 23 days

Health care plan

Flexible compensation

Training platforms

Career development plan

Referral bonuses

12/14 salary payments

Work-life balance

UST Club discounts

Descripción de la vacante

UST is seeking a highly skilled Senior Java Developer to join our engineering team in Barcelona. You will design, develop, and evolve mission-critical applications using Java 17/21, Spring Boot, and cloud-native architectures.

Work with Kafka-based event-driven systems, gRPC and Protobuf, and implement highly concurrent, performant solutions with reactive programming and structured concurrency. You will contribute to CI/CD pipelines, create technical documentation, perform testing, and

Formación

• 8+ years of professional Java development experience.
• 3+ years with Java 17/21 and modern features (records, sealed classes, pattern matching, virtual threads).
• Strong Spring Framework/Boot experience in production environments.
• Experience with reactive programming (Project Reactor/RxJava) or async patterns.
• Production experience with gRPC and Protocol Buffers, incl. streaming RPCs and schema evolution.
• Knowledge of concurrency fundamentals, executors, and thread lifecycle management.
• Solid testing practices with JUnit 5, Mockito, and AssertJ.
• Cloud experience with AWS (S3, IAM, managed Kafka, containers).
• English level C1 or higher.

Responsabilidades

• Design, develop, and maintain robust backend services with Java 17/21 and Spring Boot.
• Build scalable microservices using reactive programming and event-driven architectures.
• Develop and maintain gRPC APIs and Protobuf schemas with backward compatibility.
• Ensure high performance and proper concurrency in production systems.
• Work with Kafka-based event-driven architectures and data stores.
• Create and maintain automated tests (unit, integration, contract).
• Collaborate with cross-functional teams on architecture decisions and docs.
• Contribute to CI/CD pipelines and cloud infrastructure.
• Produce clear technical documentation and PR descriptions.

Conocimientos

Java

Spring Framework

Spring Boot

Reactive programming

gRPC

Protobuf

Kafka

AWS

Unit testing

Herramientas

Kafka

PostgreSQL

Redis

MongoDB

Protobuf

Descripción del empleo

UST is seeking a highly skilled Senior Java Developer to join our engineering team in Barcelona. You will design, develop, and evolve mission-critical applications using Java 17/21, Spring Boot, and cloud-native architectures.

Work with Kafka-based event-driven systems, gRPC and Protobuf, and implement highly concurrent, performant solutions with reactive programming and structured concurrency. You will contribute to CI/CD pipelines, create technical documentation, perform testing, and