Senior Software Engineer

Job Description:
About Rakuten:
Rakuten is a global leader in internet services, empowering individuals and businesses worldwide through a diverse ecosystem of over 70 services including e-commerce, fintech, digital content, and communications. Our mission is to contribute to society by creating value through innovation and entrepreneurship, connecting the world through our unique membership-based loyalty program and vast global reach.

About the Rakuten Global Ad Technology Department:
The Rakuten Global Ad Technology Department stands at the forefront of innovation, transforming how brands reach and influence consumers within our leading global e-commerce environment. As a fundamentally data-driven and highly cross-functional team, we build and manage a comprehensive suite of advertising products and services, leveraging Rakuten's immense first-party data and vast consumer reach to create highly effective marketing solutions. Our dynamic teams collaborate seamlessly across key hubs in Japan, Singapore, India, and China, working together to develop, optimize, and scale cutting-edge ad platforms, performance marketing tools, and sophisticated audience targeting capabilities.

Why We Are Hiring:
Rakuten's sustained success and continuous growth mean that our Global Ad Technology Department is entering a pivotal phase of expansion. We are strategically scaling our business to meet the increasing demands of the digital advertising landscape and to capitalize on a multitude of new, transformative projects lined up. These initiatives are ambitious, cutting-edge, and require top-tier engineering talent to design, build, and scale our next generation of ad platforms and services. We are expanding our engineering capabilities to strengthen our ability to innovate rapidly, ensure robust, high-performance systems, and maintain our leadership in the e-commerce advertising space. This role is key to enabling our continued innovation and growth.

The Opportunity:
We are seeking a highly skilled and experienced Senior Software Engineer to join our dynamic Global Ad Technology Department. This role is crucial for designing, developing, and deploying high-performance, scalable, and resilient advertising technology solutions that power Rakuten's global e-commerce ecosystem. You will be a key technical contributor, influencing architectural decisions, mentoring junior engineers, and driving best practices within your team.

In this role, you will tackle complex engineering challenges related to large-scale data processing, low-latency real-time systems, and highly distributed architectures. You will collaborate closely with product managers, data scientists, and other engineering teams across our global hubs to deliver innovative solutions that directly impact millions of users and advertisers worldwide.

Specifically, as a Senior Software Engineer, you will be responsible for:
Designing, developing, and deploying robust, scalable, and high-performance software solutions for our core advertising platforms and services.

Writing clean, maintainable, and efficient code using Java, Scala, Go, Python and adhering to engineering best practices.

Leading complex technical features or modules from concept to production, including requirements analysis, design, implementation, testing, and operational support.

Conducting thorough code reviews, providing constructive feedback, and ensuring code quality and adherence to architectural guidelines.

Contributing significantly to architectural discussions and technical design decisions, evaluating trade-offs and advocating for scalable and resilient solutions.

Mentoring and guiding junior and mid-level engineers, fostering a culture of technical excellence and continuous learning.

Troubleshooting and resolving complex production issues, ensuring high availability and performance of critical systems.

Collaborating effectively with cross-functional and geographically distributed teams (Product, QA, DevOps, Data Science) to deliver integrated solutions.

When you join Rakuten's Global Ad Technology Department, you're not just getting a job - you're gaining access to:

- The opportunity to build and scale mission-critical advertising platforms that operate at massive global scale.
- Exposure to cutting-edge technologies and complex, real-time data challenges in the AdTech space.
- A collaborative, innovation-driven, and intellectually stimulating environment with diverse engineering teams across multiple countries.
- Significant potential for career growth into technical leadership (Staff/Principal Engineer) or management roles within a leading global company.

Mandatory Qualifications:

- Bachelor's or Master's degree in Computer Science, Software Engineering, or a related technical field.
- Minimum 7 years of progressive experience in software development, with a significant portion in designing and building large-scale, distributed systems.
- Expert proficiency in at least one modern