Software Engineer

Rakuten Group is a global Internet services company headquartered in Tokyo, Japan, operating across a wide range of businesses including e-commerce, fintech, mobile, digital content, advertising, travel and professional sports. Founded in 1997, Rakuten has built a diverse ecosystem of services used by millions of customers worldwide. The company combines technology, data and innovation to create products and services that enrich the lives of its customers and support businesses around the world. Rakuten is also actively investing in Artificial Intelligence and Generative AI to transform its products and services. Engineers across Rakuten have opportunities to work with modern technologies including cloud computing, large language models, AI-powered search, conversational AI and intelligent agent technologies. Rakuten Web Search (RWS) is an important brand in the Rakuten ecosystem, providing search and advertising services to users in Japan. As a Software Engineer, you will work with a cross-functional team to design, develop and improve web applications and next-generation AI-powered experiences. You will be involved in the full software development lifecycle, from requirements analysis and technical design to implementation, testing, deployment and production support. The role will contribute to areas including: • Search Result Page and Web Search applications • AI-powered Search and AI Chat experiences • Advertisement and content delivery systems • Backend and frontend web applications • Business administration and analytics tools • AI/LLM-powered features and intelligent user experiences • Supporting services and APIs Responsibilities • Design, develop, test and maintain scalable full-stack web applications using Java, Spring Boot and React. • Develop backend REST APIs and microservices using Spring Boot and related Java technologies. • Develop responsive and maintainable frontend applications using React, JavaScript/TypeScript and modern frontend practices. • Work across the complete software development lifecycle, including requirements analysis, technical design, implementation, testing, deployment and production support. • Design and implement database solutions using relational databases and NoSQL/KVS technologies. • Understand business requirements and user behavior and propose technical and product improvements. • Write well-designed, testable, efficient and maintainable code following software engineering best practices. • Develop unit, integration and API tests using appropriate testing frameworks. • Participate in code reviews, technical discussions and architecture/design reviews. • Develop and maintain technical documentation including design documents, API specifications, sequence diagrams and data-flow diagrams. • Collaborate with Product Managers, Data Scientists, ML Engineers and other engineering teams to deliver AI-powered product capabilities. • Monitor, troubleshoot and provide first-level production support for applications and services. • Continuously evaluate and adopt appropriate technologies to improve system performance, reliability, scalability and developer productivity. Qualifications • 2-4 years of professional software development experience. • Strong hands-on experience in Java and Spring Boot. • Strong hands-on experience in React and modern JavaScript/TypeScript. • Experience designing and developing RESTful APIs and web applications. • Good understanding of software engineering fundamentals, object-oriented programming and design patterns. • Experience with relational databases such as MySQL/PostgreSQL and understanding of database design, query optimization and performance tuning. • Familiarity with Git and modern software development practices. • Experience with unit/integration testing frameworks such as JUnit, Mockito or equivalent. • Good understanding of web technologies including HTTP, REST, JSON, HTML and CSS. • Basic understanding of secure coding practices and application security. • Experience working in an Agile/DevOps development environment. • Ability to understand business requirements and translate them into technical solutions. • Ability to write technical documentation such as design documents, API specifications and sequence diagrams. • Strong problem-solving and analytical skills. • Good communication and collaboration skills, with the ability to work effectively in a multicultural and cross-functional environment. • A proactive “can-do” attitude with a strong sense of ownership. Rakuten is an equal opportunities employer and welcomes applications regardless of sex, marital status, ethnic origin, sexual orientation, religious belief, or age.