Senior Java Backend Engineer — Spring Microservices & Cloud

Quantum Technologies. LLC; Chicago (IL); On-site; USD 120,000 - 160,000; Full time

Job summary

Quantum Technologies. LLC is seeking an experienced Java Backend Developer to design, develop, and maintain scalable backend applications using Java, Spring Boot, and microservices.

You will build REST APIs, integrate with databases and cloud services, and collaborate with frontend, QA, and DevOps teams in an agile environment. The role emphasizes performance, security, testability, and reliable deployment on containerized platforms with AWS/Azure/GCP, Kafka or messaging systems, and CI/CD

Qualifications

• Experience designing, developing and maintaining scalable backend applications using Java and Spring Boot.
• Build robust RESTful APIs for enterprise applications.
• Develop and maintain a Microservices-based architecture.
• Implement business logic with Java, J2EE, and OO concepts.
• Work with Spring Framework (Spring MVC, Spring Data JPA, Hibernate).
• Design and optimize database schemas, queries and stored procedures.
• Integrate backend services with third-party APIs and external systems.
• Implement authentication/authorization with Spring Security, OAuth 2.0, and JWT.
• Develop asynchronous processing with Kafka, RabbitMQ, or similar messaging systems.
• Improve performance via caching and code optimization.
• Write unit/integration tests using JUnit and Mockito.
• Deploy/manage backend apps on AWS, Azure, or GCP.
• Operate with Docker and Kubernetes for containers.
• Participate in code reviews and maintain coding standards.
• Troubleshoot production issues and fix defects.
• Collaborate with cross-functional teams in Agile environments.

Responsibilities

• Design, develop, and maintain backend applications using Java and Spring Boot.
• Build scalable and secure RESTful APIs for enterprise applications.
• Develop and maintain Microservices-based architecture.
• Implement business logic using Java, J2EE, and object-oriented programming concepts.
• Work with Spring Framework, Spring MVC, Spring Data JPA, and Hibernate.
• Design and optimize database schemas, queries, and stored procedures.
• Integrate backend services with third-party applications and external APIs.
• Implement authentication and authorization using Spring Security, OAuth 2.0, and JWT.
• Develop asynchronous processing using Kafka, RabbitMQ, or messaging systems.
• Improve application performance through caching and code optimization.
• Write unit and integration tests using JUnit and Mockito.
• Deploy and manage backend applications on AWS, Azure, or GCP.
• Work with Docker and Kubernetes for containerization and deployment.
• Participate in code reviews and maintain coding standards.
• Troubleshoot production issues and resolve application defects.
• Collaborate with cross-functional teams in Agile development environments.

Skills

Java

Spring Boot

Microservices

REST APIs

Cloud technologies

Database design

OAuth 2.0 / JWT

Kafka / RabbitMQ

JUnit / Mockito

Docker

Kubernetes

Tools

Docker

Kubernetes

AWS

Azure

GCP

Spring Framework

Hibernate

Kafka

RabbitMQ

Job description

Quantum Technologies. LLC is seeking an experienced Java Backend Developer to design, develop, and maintain scalable backend applications using Java, Spring Boot, and microservices.

You will build REST APIs, integrate with databases and cloud services, and collaborate with frontend, QA, and DevOps teams in an agile environment. The role emphasizes performance, security, testability, and reliable deployment on containerized platforms with AWS/Azure/GCP, Kafka or messaging systems, and CI/CD