Senior Java Developer

IMPACT AI TECHNOLOGIES PTE. LTD.; Singapore; On-site; SGD 110,000 - 170,000; Full time

Job summary

IMPACT AI TECHNOLOGIES PTE. LTD. seeks a Senior Backend Java Developer focused on microservices, distributed systems, and backend engineering.

You will design, build, and scale microservices-based RESTful APIs and enterprise backend components using Java, Spring Boot, and Spring Data JPA. You will implement robust patterns, ensure performance with asynchronous messaging, optimize databases (SQL/NoSQL), and write unit tests. Experience with Docker and Redis is a plus.

Qualifications

• 5+ years of hands-on Java software development
• Deep knowledge of Collections, Streams API, Multithreading/Concurrency
• Experience with Spring Boot, Spring Core, Spring MVC
• Understanding microservices architecture and RESTful design
• Experience with message brokers and event streaming
• Testing with JUnit/Mockito
• Containerization basics and CI/CD pipelines

Responsibilities

• Design, build, and maintain scalable microservices and distributed backend services
• Implement clean microservice architectural patterns and domain-driven design
• Author OpenAPI/Swagger documentation for REST endpoints
• Leverage concurrency utilities and asynchronous messaging for performance
• Diagnose memory leaks, thread contention, and GC bottlenecks in containers
• Design and optimize relational and NoSQL database schemas
• Manage data persistence with Spring Data JPA
• Write tuned SQL queries and configure caching (Redis)
• Implement resiliency patterns like Circuit Breakers and Retry policies
• Ensure security with OAuth2/JWT and data sanitization
• Build logging, health checks, and application metrics; maintain test coverage

Skills

Java

Spring Boot

Spring Core

Spring MVC

REST APIs

Microservices

Distributed systems

Multithreading/Concurrency

JUnit/Mockito

OpenAPI/Swagger

Tools

Docker

Redis

Swagger/OpenAPI

Job description

Position Overview

We are seeking an experienced Senior Backend Java Developer with a specialized focus on microservices architecture, distributed systems, and backend engineering. In this role, you will design, build, and scale microservices-based RESTful APIs and enterprise backend components. You will focus on service communication, asynchronous messaging, optimizing database interactions, and driving sound microservice design principles across the stack.

Key Responsibilities

• Design, build, and maintain scalable microservices and distributed backend services using Java and the Spring / Spring Boot ecosystem.
• Implement clean microservice architectural patterns, domain-driven design, and reusable software modules.
• Author standard OpenAPI/Swagger documentation for REST endpoints and inter-service contracts.
• Leverage Java concurrency utilities and asynchronous messaging to ensure efficient application performance.
• Diagnose, debug, and resolve memory leaks, thread contention, and garbage collection bottlenecks in containerized environments.
• Design and optimize relational and NoSQL database schemas tailored for decoupled microservices.
• Manage data persistence and transactional boundaries across distributed services using Spring Data JPA.
• Write tuned SQL queries, establish effective database indexing, and configure caching strategies (e.g., Redis).
• Implement robust microservice resiliency patterns including Circuit Breakers, Rate Limiting, and Retry policies.
• Implement standard API and service security mechanisms (OAuth2, JWT authentication, authorization, and data sanitization).
• Build structured logging, health checks, and application metrics using standard logging frameworks.
• Write clean, maintainable, modular, and unit-tested microservice code using JUnit and Mockito.
• Participate in code reviews, technical architecture reviews, and maintain test coverage across application modules.

Requirements

• 5+ years of hands-on software development experience using Java with deep knowledge of Collections, Streams API, Multithreading/Concurrency, and Exception Handling.
• Strong expertise in Spring Boot, Spring Core, Spring MVC, and dependency injection paradigms.
• Deep understanding of microservices architecture, distributed systems design principles, and RESTful architectural styles.
• Advanced proficiency in Spring Data JPA, raw SQL query tuning, and database migration tooling.
• Practical, hands-on experience with message brokers and event streaming architectures.
• Solid grasp of Design Patterns, TDD/unit testing principles (JUnit, Mockito), containerization basics, and CI/CD deployment pipelines.