Job Advert Title: Software Engineer (Full stack)
Location: Nihonbashi, Tokyo
Division: DigitalX
Employment Class: Permanent
Description
【募集の背景 / Purpose & Scope】
We are looking for an ambitious backend engineer to help shape the future of Astellas by building the production backbone of our Generative AI platforms. This is a high-impact role at the heart of our digital transformation, where you will design, deploy, and scale systems that enable cutting-edge AI to make a tangible difference across commercial, manufacturing, and medical operations.
In this role, you’ll own the challenge of bringing state-of-the-art AI into production, integrating diverse data sources, architecting resilient APIs, and ensuring scalable, reliable service delivery at enterprise level. You’ll have the autonomy to make big decisions, continuously improve systems, and explore new technologies while collaborating with a dynamic, globally distributed team of innovators across multiple time zones.
This is more than backend engineering. It’s an opportunity to drive real transformation at scale, experiment with SOTA AI, and grow in an environment that values continuous learning, global collaboration, innovation, and impact.
【職務の内容 / Essential Job Responsibilities】
（雇入れ直後）
・ End-to-End Development: Design, develop, and maintain scalable fullstack applications that connect intuitive, performant user interfaces with robust backend services powering Generative AI platforms.
・ Frontend Engineering: Build modern, responsive, and accessible UIs using frameworks such as React, Next.js, or Vue, delivering seamless user experiences for diverse stakeholders across Astellas’ commercial, medical, and manufacturing operations.
・ Backend & API Integration: Develop and optimize secure, scalable APIs; integrate with data pipelines, vector databases, and AI model endpoints to bring Generative AI into production.
・ Cloud-Native Deployment: Deploy, operate, and scale fullstack applications in cloud environments (AWS, GCP, or Azure), leveraging CI/CD pipelines, containerization, and infrastructure-as-code.
・ Data Handling: Work with structured and unstructured data to support AI-driven workflows and ensure smooth data flow between frontend, backend, and ML systems.
・ Collaboration in Global Teams: Partner with a globally distributed team of engineers, designers, and data scientists to deliver high-impact solutions; contribute to code reviews, shared standards, and technical decision-making.
・ Monitoring & Continuous Improvement: Implement observability, logging, and performance monitoring for fullstack applications; proactively identify and resolve issues while driving continuous improvement.
・ Innovation & Learning: Explore GenAI technologies and bring state-of-the-art approaches into production systems.
・ Mentorship & Knowledge Sharing: Support and mentor peers, fostering a culture of collaboration, craftsmanship, and continuous growth across the team.
（変更の範囲）
会社内での全ての業務
【就業環境に関する要件 / Specific Physical or Environmental Requirements】
At Astellas we recognize the importance of work/life balance, and we are proud to offer a hybrid working solution allowing time to connect with colleagues at the office with the flexibility to also work from home. We believe this will optimize the most productive work environment for all employees to succeed and deliver. Hybrid work from certain locations may be permitted in accordance with Astellas’ Responsible Flexibility Guidelines.
【応募要件 / Qualifications】
＜必須 / Required＞
・ Education: Bachelor’s degree in Computer Science, Software Engineering, or a related technical field (or equivalent practical experience).
・ Professional Experience: Minimum 4 years of experience in software engineering, with proven ability to deliver production-grade applications.
・ Frontend Expertise: Proficiency in modern JavaScript/TypeScript frameworks (e.g., React, Next.js, Vue) with a strong focus on building performant, responsive, and accessible user interfaces.
・ Backend & API Development: Solid experience developing secure, scalable APIs, with strong Python and Node.js skills for backend services.
・ Cloud-Native Deployment: Hands-on experience deploying applications to cloud platforms (AWS, GCP, or Azure), leveraging containerization, CI/CD pipelines, and infrastructure-as-code.
・ Data Integration: Ability to work with structured and unstructured data and integrate with SQL/NoSQL databases to support AI-driven workflows.
・ Scalable Software: Strong understanding of software design principles, distributed systems, performance optimization, and security best practices.
・ Collaboration in Global Teams: Demonstrated ability to thrive in dynamic, globally distributed teams, contributing to agile processes, code reviews, and shared technical decisions.
・ Continuous Learner: Curiosity and adaptability to stay ahead of modern development trends, Generative AI integration, and cloud-native best practices.
＜歓迎 / Preferred＞
・ Generative AI & ML Integration: Experience working on projects involving Generative AI applications or machine learning workflows (e.g., integrating LLMs, model endpoints, or vector databases).
・ Advanced Frontend Skills: Familiarity with Real-Time application development for complex data and AI-driven insights. WebRTC, WebSocket.
・ Data Engineering Knowledge: Understanding of ETL pipelines, real-time data streaming, and tools for efficient data ingestion and transformation.
・ Cloud AI Services: Experience leveraging AI/ML services in cloud environments for deploying and scaling applications.
・ Observability & Reliability: Familiarity with monitoring and logging tools to ensure performance, availability, and reliability of fullstack systems.
・ Modern Frameworks & Tools: Exposure to emerging developer frameworks and tools (e.g., LangChain, Hugging Face, serverless platforms) and a passion for applying them in production.
・ Open Source & Community Engagement: Contributions to open-source projects or active engagement with the fullstack/AI developer community.
【応募書類 / Application Documents】
和文履歴書・和文職務経歴書・英文レジュメ
Both Japanese and English Resumes are needed
【選考プロセス / Selection details】
書類選考 → 1次面接 → 2次面接 → 最終面接
※変更の可能性もございますので、予めご了承下さい。
CV screening → First interview → 2nd Interview → Final interview
*Please be advised that there might be a change in the process.
【勤務地 / Location】
（雇入れ直後）
東京都中央区 アステラス製薬 日本橋事業所 本社
Nihonbashi, Tokyo
（変更の範囲）
会社の定める事業場および自宅
【勤務開始日 / Start Date】
応相談
Will be decided according to the candidate's flexibility
【契約期間 / Contract Duration】
期間の定めなし
Not limited to specified period
【試用期間 / Probation Period】
試用期間原則なし
No probation period in principle
【給与 / Salary】
①基本給：当人の経歴・技術・技能等を考慮して決定
②裁量労働制の場合：裁量労働手当として職務グレードに応じて50,000～100,000円支給
③フレックスタイム制の場合：月間の所定労働時間を超えて勤務する時間に対して時間外勤務手当を支給
①Base salary: will be decided by the candidate's experience, skill and capability.
②When Discretionary Work System is applied: Discretionary work allowance will be paid.(50,000～100,000yen, based on the Grade)
③When Flextime System is applied: Overtime allowance will be paid for time worked in excess of prescribed working hours.
【昇給 / Salary Raise】
有り
【賞与 / Bonus】
有り
【諸手当 / Allowance】
裁量労働手当、住宅手当、通勤手当 等
Discretionary work allowance, Housing allowance, Commutation allowance, etc.
【勤務時間 / Working Hours】
8:45～17:45（月～木）、8:45～16:00（金）、企画業務型 裁量労働制
裁量労働制の場合、所定労働時間を働いたものとみなす
8:45～17:45（Mon～Thu）、8:45～16:00（Fri）
Discretionary Work System
【休日 / Holidays】
完全週休２日制（土曜・日曜）、祝日、5月1日、夏季、年末年始
Weekends(Sat and Sun), holidays, May 1st, summer vacation, New Year holidays
【休暇 / Vacation Leave】
年次有給休暇、育児休業制度、介護休業制度 等
Annual paid leave, childcare leave system, nursing care leave system, etc.
【福利厚生 / Welfare】
雇用保険、労災保険、厚生年金、健康保険、共済会制度、社宅制度、持株会制度、財形貯蓄制度 等
Employment Insurance, Industrial Accident Compensation Insurance, Welfare Pension Insurance, Health Insurance, Mutual Aid Association System, Company Housing System, Employee Shareholder Association System, Property Accumulation Savings System
【アステラス製薬 採用サイト/ Career web site】
https://re-jp.astellas.com/jp/recruit/newgraduates/
For more information about Astellas, please visit our career web site.
"We are an equal opportunity employer and all qualified applicants will receive consideration for employment without regard to race, color, religion, sex, national origin, disability status, protected veteran status, or any other characteristic protected by law."