Senior Java Backend Engineer
Job Description
We are looking for a Senior Java Backend Engineer to join our team and play a key role in modernising and improving a live, enterprise-grade platform. You will work on backend services, APIs, integrations, performance, reliability, security, and the gradual modernization of legacy systems.
This is a hands-on engineering role suited to an experienced Java developer who enjoys solving complex technical problems and working with modern backend technologies.
Key Responsibilities
Develop, maintain, and improve backend services and APIs using Java and Spring Boot.
Work with existing legacy systems and gradually modernise code, frameworks, and dependencies.
Design and implement scalable, reliable REST APIs and backend services.
Improve application performance, stability, and maintainability.
Work with relational databases and improve database queries, schemas, and data access.
Develop and maintain asynchronous processing and message-based integrations.
Implement automated unit, integration, and API tests and improve overall test coverage.
Identify and remediate security vulnerabilities and follow secure development practices.
Upgrade outdated Java libraries and frameworks to supported versions.
Troubleshoot production issues and contribute to root-cause analysis and long-term fixes.
Collaborate with other backend engineers, DevOps, QA, and product teams.
Contribute to architectural and technical decisions as the platform evolves.
Requirements
Required Experience & Qualifications
5+ years of professional software engineering experience, primarily with Java.
Strong hands-on experience with Java 8+, preferably Java 17 or newer.
Strong experience with Spring Boot and the broader Spring ecosystem.
Good knowledge of REST APIs, HTTP, JSON, and backend application architecture.
Solid experience with relational databases and SQL.
Experience with JPA/Hibernate or similar persistence technologies.
Experience writing unit and integration tests using tools such as JUnit and Mockito.
Understanding of asynchronous processing, messaging, or event-driven systems.
Good understanding of software design principles, clean code, and common design patterns.
Experience working with Git and modern CI/CD practices.
Strong problem-solving and debugging skills.
Comfortable working with legacy code and gradually improving existing systems.
Good communication skills and ability to work effectively within an engineering team.
Previous experience leading, mentoring, or coordinating software engineers.
About Division5
For 10+ years, we've created solutions that improve lives. We tackle complex projects others avoid. Our DNA: boldness and courage. We say yes when others say no.
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