Java Backend Engineer
Posted 12 Oct 2026
Advertised as “Senior Java Backend Engineer”
BranchFactor Summary
The original posting with the fluff stripped out
- Expected experience
- 3–5 yrs
- Management level
- Individual contributor
- Employment
- Hybrid
No salary listed for this role.
At Quento Technologies S.A., the ICT arm of the Qualco Group, we deliver comprehensive and innovative solutions across AI, Digital Engineering, Cloud, and Cybersecurity, helping businesses accelerate digital transformation. With a presence in Greece, Luxembourg, and Belgium, and backed by the expertise of the Qualco Group, we combine deep technical knowledge with strategic partnerships to support business growth.
At Quento Technologies S.A. we empower our people to innovate and lead in delivering transformative ICT solutions to our clients worldwide. Quento Technologies S.A. seeks a highly motivated and experienced Senior Java Backend Engineer to design, build, and maintain modern, scalable backend services. You will work on microservice-based architectures, event-driven systems, and cloud-native applications using modern Java and Spring Boot, collaborating closely with DevOps and platform teams.
Your responsibilities will entail:
- Design and develop backend microservices using Java 21 and Spring Boot 3.x;
- Build and maintain RESTful APIs with clear error handling and documented OpenAPI/Swagger specifications;
- Implement gRPC services and clients, including Protobuf schema design;
- Develop event-driven solutions using Apache Kafka consumers and producers;
- Integrate backend services with external systems (OIC, Salesforce, SAP ISU);
- Implement authentication and authorization using OAuth 2.0 / OIDC, including token validation and role-based access;
- Write unit and integration tests using JUnit 5, Mockito, and Testcontainers;
- Collaborate with DevOps teams on containerized deployments in Docker and Kubernetes;
- Ensuring that all activities and duties are carried out in full compliance with regulatory requirements and supporting the continued implementation of the Group Anti-Bribery and Corruption Policy.
Requirements
- University degree in Computer Science, Engineering, or a related field;
- 3–5+ years of experience in backend development;
- Strong hands-on experience with Java (preferably Java 21) and modern language features;
- Proven experience with Spring Boot (microservices, REST controllers, data access layers, security);
- Experience migrating applications from older Java versions (e.g., Java 11);