Senior Backend Java Engineer - API & Architecture

Optimum Solutions Pte Ltd; Singapore; On-site; SGD 90,000 - 130,000; Full time

Job summary

Optimum Solutions Pte Ltd is seeking an experienced Backend Java Developer to design, build, and maintain high-throughput, secure RESTful APIs and enterprise backend components. You will focus on scalable code, multi-database interactions, and strong OOP and functional practices across the stack.

The role emphasizes Java 11+/17+, Spring Boot, REST API design, and robust database work with relational and NoSQL systems, plus security and observability considerations.

Qualifications

• 5+ years of hands-on Java development with Java 11/17+ and strong core Java knowledge.
• Experience with Spring Boot, Spring Core, Spring MVC and DI.
• Proficient in designing RESTful APIs, database design, and asynchronous programming.

Responsibilities

• Design, build, and maintain RESTful APIs and backend services using Java (11+) and the Spring Boot framework.
• Implement clean architectural patterns, object-oriented design principles (SOLID), and reusable modules.
• Author OpenAPI/Swagger docs for REST endpoints and internal contracts.

Skills

Java

Spring Boot

REST APIs

Concurrency

SQL/Databases

Spring Data JPA/Hibernate

OpenAPI/Swagger

OAuth2/JWT Security

JUnit/Mockito

Logging/Monitoring

Tools

Kafka/RabbitMQ

Flyway/Liquibase

Docker

Redis

Maven/Gradle

Job description

Optimum Solutions Pte Ltd is seeking an experienced Backend Java Developer to design, build, and maintain high-throughput, secure RESTful APIs and enterprise backend components. You will focus on scalable code, multi-database interactions, and strong OOP and functional practices across the stack.

The role emphasizes Java 11+/17+, Spring Boot, REST API design, and robust database work with relational and NoSQL systems, plus security and observability considerations.