Senior Java Backend Engineer: Cloud Microservices, Kafka & Security

Qualco Group; Kentucky; Hybrid; USD 110,000 - 180,000; Full time

Benefits offered by this job

Ticket restaurant card

Annual bonus programs

Modern IT equipment

Health insurance

Job summary

Quento Technologies S.A., the ICT arm of the Qualco Group, seeks a Senior Java Backend Engineer to design, build, and maintain scalable backend services. You will work on microservice architectures, event-driven systems, and cloud-native apps using Java 21 and Spring Boot, collaborating with DevOps and platform teams.

Your responsibilities include designing RESTful APIs, implementing gRPC, Kafka-based event processing, and integrating with OIC, Salesforce, and SAP ISU.

Qualifications

• Bachelor's degree in computer science, engineering, or related field.
• 3–5+ years backend development experience.
• Strong hands-on with Java (preferably Java 21) and modern language features.
• Proven experience with Spring Boot microservices, REST controllers, data access, and security.
• Experience migrating apps from older Java versions (e.g., Java 11).
• Solid knowledge of Kafka-based event-driven architectures.
• Experience with PostgreSQL, Azure Cosmos DB, and Redis.
• Good understanding of containerization (Docker) and Kubernetes.
• Strong backend security knowledge (OAuth2, OIDC, RBAC).
• Experience writing automated unit/integration tests.
• Experience in Agile environment.

Responsibilities

• Design and develop backend microservices using Java 21 and Spring Boot 3.x.
• Build and maintain RESTful APIs with OpenAPI/Swagger specifications.
• Implement gRPC services/clients and Protobuf design.
• Develop event-driven solutions with Apache Kafka.
• Integrate with external systems (OIC, Salesforce, SAP ISU).
• Implement OAuth 2.0/OIDC authentication/authorization.
• Write unit and integration tests with JUnit 5, Mockito, Testcontainers.
• Collaborate with DevOps on Docker/Kubernetes deployments.
• Ensure compliance with group policies and regulatory requirements.

Skills

Java 21

Spring Boot

Microservices

REST APIs

OAuth 2.0 / OIDC

Kafka

Testing

DevOps familiarity

Education

University degree in CS/Engineering

Tools

OpenAPI/Swagger

gRPC

Protobuf

PostgreSQL

Redis

Docker

Kubernetes

Job description

Quento Technologies S.A., the ICT arm of the Qualco Group, seeks a Senior Java Backend Engineer to design, build, and maintain scalable backend services. You will work on microservice architectures, event-driven systems, and cloud-native apps using Java 21 and Spring Boot, collaborating with DevOps and platform teams.

Your responsibilities include designing RESTful APIs, implementing gRPC, Kafka-based event processing, and integrating with OIC, Salesforce, and SAP ISU.