TOPPA SOLUTIONS is a software solutions development service provider for businesses looking to develop or improve their operations through technology. Whether you need to build a new software application, modernize existing systems, or consult on strategy, we have the expertise to help you achieve your objectives. Bring your software ideas into reality with TOPPA' consulting and engineering capabilities. Our blend of technology, design and management expertise ensures a seamless and consistent experience in terms of software design, development, communication, and project management.Currently, TOPPA SOLUTIONS has established an office in Japan and opened a branch in Da Nang to develop business activities in the coming years. Therefore, TOPPA SOLUTIONS is strengthening and promoting the recruitment plan to recruit talents with the same vision to accompany TOPPA SOLUTIONS in carrying out the great mission and challenges ahead.Role OverviewDesign, build, and operate backend services for large-scale products using the Java ecosystem. You will own end-to-end delivery—architecture, implementation, code quality, performance, and reliability—while collaborating closely with Frontend, QA, DevOps, and BA teams (onshore/offshore).Key ResponsibilitiesDesign, develop, and maintain backend services using Java Core, Spring Boot, Spring MVC.Implement RESTful APIs, integrate with external systems, and ensure scalability, performance, and reliability.Participate in code reviews, uphold coding standards, and drive continuous improvement.Work with relational databases (MS SQL Server, PostgreSQL) and NoSQL (MongoDB); optimize queries, ensure data consistency, and manage migration scripts.Collaborate with DevOps on CI/CD pipelines, environment setup, observability, and runtime monitoring.Debug and resolve production issues in partnership with QA/Support; provide operational runbooks where needed.Coordinate across Frontend, QA, DevOps, BA to deliver seamlessly within Agile sprints.Support UAT and production releases according to customers’ maintenance windows.