Software Engineer (Backend)

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） ・ API Development & Integration: Build and scale secure RESTful and GraphQL APIs that power Generative AI applications, enabling seamless integration between AI models, data pipelines, and user-facing products. ・ Production-Grade AI Deployment: Lead the design and deployment of backend systems that bring state-of-the-art Generative AI into production, ensuring performance, scalability, and enterprise-grade reliability. ・ Data Engineering & Integration: Manage diverse data formats and integrate with SQL/NoSQL databases, vector stores, and streaming platforms to optimize data ingestion and retrieval for AI-driven use cases. ・ MLOps & DevOps Automation: Develop CI/CD pipelines, implement containerization (Docker/Kubernetes), and automate deployment workflows to accelerate experimentation, continuous improvement, and reliable delivery of AI-powered services. ・ Collaboration & Technical Leadership: Partner with data scientists, ML engineers, and product teams to translate cutting-edge research into production-ready systems; mentor teammates and champion best practices in backend and AI engineering. ・ Monitoring, Reliability & Continuous Improvement: Establish observability, monitoring, and alerting for backend and AI workloads; diagnose issues proactively; and drive continuous optimization of performance, cost, and developer experience. （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, or a related technical field (or equivalent practical experience). ・ Backend Engineering Expertise: Minimum 4 years of professional experience in backend development, with strong proficiency in Python and a track record of delivering production-grade systems. ・ API & System Design: Deep expertise in designing and implementing secure, scalable APIs that power enterprise and AI-driven applications. ・ Cloud Deployment: Hands-on experience deploying, operating, and scaling backend services in cloud environments (AWS, GCP, or Azure), including containerization (Docker/Kubernetes) and infrastructure-as-code. ・ Production-Ready Practices: Proficiency with CI/CD pipelines, automated testing, and monitoring systems to ensure reliable and efficient software delivery. ・ Data Fluency: Strong experience working with structured and unstructured data and integrating with SQL/NoSQL databases, plus familiarity with modern data infrastructure for AI/ML workloads. ・ Scalable Software: Solid grounding in distributed systems, software design patterns, security best practices, and performance optimization at scale. ・ Collaboration & Growth Mindset: Comfortable working in agile, cross-functional teams partnering with frontend engineers, data scientists, and product managers and mentoring peers in backend best practices. ・ Continuous Learner: Demonstrated curiosity and adaptability in adopting emerging technologies, especially in Generative AI, MLOps, and cloud-native development. ＜歓迎 / Preferred＞ ・ Generative AI & ML Experience: Hands-on experience contributing to machine learning projects or deploying Generative AI applications (e.g., working with LLMs, vector databases, or model serving frameworks). ・ Cloud AI Expertise: Deeper knowledge of AWS, Azure, or Google Cloud Platform services for AI/ML (e.g., SageMaker, Vertex AI, Azure ML), with experience optimizing cost, performance, and scalability in cloud-native deployments. ・ Data Engineering & ETL: Familiarity with ETL processes, streaming pipelines, and modern data tools for efficient data ingestion, transformation, and integration into AI/ML workflows. ・ Observability & Reliability: Understanding and practical use of application monitoring, logging, and tracing tools (e.g., Prometheus, Grafana, ELK, Datadog) to ensure system health and proactive troubleshooting. ・ Innovation Mindset: Passion for experimenting with emerging frameworks (LangChain, LlamaIndex, Hugging Face, etc.) and applying state-of-the-art research to solve real-world challenges.