Senior Fullstack Engineer

Job Description – Senior Fullstack Engineer
Link Platform and Operations Engineering Section -LINK Department
(RS Link Division)

About Organization:
Department Overview
LINK Department is a highly diverse and technologically advanced organization within Rakuten
Symphony, Inc.. We are proud to have members from over 10 countries, creating a rich cultural
tapestry. Our division values diversity and fosters a culture of open respect that encourages
creativity.
Our product – LINK is a comprehensive communication and ecosystem app for Rakuten Mobile
customers. It offers various services such as calls, messaging, contact management, voicemail,
official accounts, news, cash transfers, and point rewards. LINK Desktop enhances the
communication experience on PCs and laptops.
Why We Hire
We are seeking a Senior Fullstack Engineer to join our dynamic and innovative development
team. In this pivotal role, you will be instrumental in designing, developing, and maintaining our
robust and scalable web applications across both the front-end and back-end.

We’re looking for an individual who not only excels in hands-on development but also
demonstrates a proactive mindset, strong problem-solving abilities, and a commitment to
elevating technical standards. You will have the opportunity to mentor junior engineers, drive
architectural discussions, and contribute significantly to our technical roadmap and best
practices.
Position Details:
Position Overview
As a Senior Fullstack Engineer, you will be a pivotal member of our dynamic development team,
responsible for the end-to-end architectural design, development, and operational excellence of
our web applications. You will work across the entire stack, from crafting intuitive user interfaces
to building robust backend systems and ensuring seamless deployment. Collaborating closely
with cross-functional teams, you will translate complex requirements into technical solutions,
drive innovation, and contribute significantly to the successful delivery of our products. We are
looking for an individual who not only excels in hands-on development but also has a passion

for guiding technical direction and fostering a culture of excellence.

Key Responsibilities
– Architectural Leadership: Participate in and lead architectural discussions, contributing to the
overall technology roadmap and ensuring the scalability, reliability, and security of our systems.
– End-to-End Development: Design, develop, and maintain high-quality, scalable web
applications across both front-end and back-end, utilizing modern frameworks and best
practices.
– Backend Expertise: Develop and maintain resilient RESTful APIs and microservices using
programming languages such as Java, Kotlin, or NodeJS, and related frameworks (Spring,
ExpressJS).
– Frontend Prowess: Craft intuitive, responsive, and accessible user interfaces using modern
JavaScript frameworks like React (including latest frameworks like Remix), Angular, or Vue.js,
focusing on an exceptional user experience.
– Database Management: Design, optimize, and maintain database schemas and queries for
performance and scalability using relational (e.g., MySQL, PostgreSQL) and/or NoSQL (e.g.,
Cassandra) databases.
– Cross-functional Collaboration: Partner closely with product managers, designers, QA, and
DevOps teams to gather requirements, provide constructive feedback, and ensure successful
product delivery.
– Code Quality & Best Practices: Write clean, efficient, well-tested, and reusable code. Conduct
thorough code reviews to maintain high quality standards and share knowledge within the team.
– Cloud & DevOps: Deploy and manage applications on cloud infrastructure platforms like
Kubernetes (K8s), collaborating with DevOps to streamline deployment, monitoring, and scaling
processes.
– Mentorship & Growth: Provide guidance and mentorship to junior engineers, fostering their
growth and development, and contributing to a collaborative and continuous learning
environment.
– Innovation & Trends: Stay abreast of the latest industry trends, technologies, and best
practices across the full web development stack (front-end, back-end, databases, cloud), and
proactively apply them to enhance our applications.
– Security & Compliance: Implement robust security measures to protect data and ensure
compliance with industry standards across all layers of the application.
Work Environment
Link Department is an organization of approximately 105 members, consisting of about 80 men
and 25 women. Our team comprises a wide range of age groups, from their 20s to 50s.
With offices in Japan, India, and Singapore, it is a highly multinational department where about
90% of the employees are non-Japanese nationals.
Our work environment is built on a foundation of collaboration and mutual support. We believe
that the best ideas come from working together, sharing knowledge, and celebrating each
other’s successes. We actively encourage professional development and provide opportunities

for growth, empowering our employees to reach their full potential. We’re committed to creating
a space where everyone feels valued, respected, and inspired to contribute their best work.
Minimum Qualifications:
– Bachelor’s degree in Computer Science, Engineering, or a related field (or equivalent work
experience).
– 10+ years of progressive experience in software development, with a significant portion in
full-stack web applications.
– Minimum 3 years of experience operating in a Senior Engineer role, demonstrating technical
leadership and mentorship.
– Strong proficiency in programming languages such as Java, Kotlin, or NodeJS, with proven
experience in designing, developing, and maintaining robust REST APIs and microservices.
– Strong proficiency in HTML, CSS, and JavaScript (ES6+), with extensive experience in
modern JavaScript frameworks like React (including frameworks like Remix), Angular, or Vue.js.
Familiarity with state management libraries (e.g., Redux, MobX) is essential.
– In-depth knowledge of database technologies (e.g., MySQL, PostgreSQL, Cassandra) and
proven experience in designing schemas and optimizing queries for performance.
– Solid understanding of software development principles, design patterns, data structures,
algorithms, and best practices across the full-stack.
– Excellent analytical, problem-solving, and decision-making skills, with the ability to thrive in a
fast-paced, collaborative environment.
– Strong communication and interpersonal skills, with the ability to effectively articulate complex
technical concepts and solutions to both technical and non-technical stakeholders.
– Experience with Agile development methodologies.
Preferred Qualifications:
– Master’s degree in Computer Science, Engineering, or a related technical field.
– Demonstrated experience with distributed systems and microservice architectures at scale.
– Proven track record in performance tuning and optimization across both frontend and backend
systems.
– Experience designing and implementing scalable and maintainable full-stack architectures.
– Hands-on experience with monitoring, logging, and tracing tools (e.g., Prometheus, Grafana,
ELK stack, Jaeger).
– Understanding of common architectural patterns for building resilient and observable
applications.
– Experience with CI/CD pipelines and automated deployment processes.
– Familiarity with infrastructure as code (IaC) tools (e.g., Terraform, CloudFormation).
– Experience with security best practices for web applications and APIs (OWASP Top 10).
– Experience mentoring junior engineers or leading small technical initiatives.
– Active participation in open-source projects or contributions to the wider tech community.