楽天グループ株式会社：1029348　Backend Engineer – AI for Business Department (AI4B)

会社名

楽天グループ株式会社

会社概要

未来を信じ、より良い明日を創っていく。
イノベーションを通じて、人々と社会をエンパワーメントする。私たちは、そんな想いを大切に世界の人々に喜びと楽しさを届けます。
楽天は、E コマース、FinTech、デジタルコンテンツ、通信など、70 を超えるサービスを展開し、世界10 億以上のユーザーに利用されています。
これら様々なサービスを、楽天会員を中心としたメンバーシップを軸に有機的に結び付け、他にはない独自の「楽天エコシステム」を形成しています。ダイバーシティ推進は、楽天にとって最優先の企業戦略のひとつです。従業員の出身は70カ国・地域以上。世界中からユニークで多様な文化的背景や視点を持つ優秀な人材が集まり、イノベーションの原動力になっています。社内カフェテリアにはベジタリアン、ハラル対応のメニューを用意。礼拝所（Prayer room）もあります。
また、仕事と育児の両立支援や、障がい者雇用・活躍促進も積極的に推進。社内のLGBT（※1）当事者やアライ（※2）に対して、情報共有やサポート体制の強化も進めています。誰もが自分らしく力を最大限発揮して働ける。それが楽天のダイバーシティです。

70を超えるサービスを提供し、世界30カ国にサービス展開拠点を持ち、従業員の出身国・地域数は100を超え、オープンポジション制度を活用して多様なキャリアを描くことができる点も魅力です。
フレックスタイム制度、事情に応じたリモートワークの活用が可能です。本社には託児所やフィットネスジム、三食無料で利用可能なカフェテリアが併設されるなど、社員を支える環境が整備されています。

ポジション

1029348　Backend Engineer - AI for Business Department (AI4B)

仕事内容

Department Overview 
Rakuten provides a variety of services in e-commerce, fintech, digital content, and communications to users worldwide. Our AI for Business Department operates as a center of excellence, focusing on developing and deploying innovative solutions that combine frontier technologies to enhance our products and services across business units. We are a diverse team of engineers who are passionate about applying their skills to make a significant difference and potentially change society for the better through AI

Within AI4B, our AI Engineering Section serves as the foundation that powers innovation, with the mission to design, build, and scale the technical backbone of our products. Focused on backend systems, DevOps practices, and cloud infrastructure, we ensure reliability, performance, and adaptability—enabling teams to move fast while maintaining operational excellence. Are you passionate about building scalable, high-performance AI application backends and APIs? Join us as a Backend Engineer and help shape the future of AI-powered solutions across our ecosystem

Position Details 
As a Backend Engineer, you will design and operate scalable systems that handle complex AI workloads, integrate with multiple LLM providers, and meet strict security, latency, and reliability requirements across Rakuten's businesses. You'll work with both cutting-edge AI technologies and proven solutions like Python, FastAPI, PostgreSQL, and Redis, while implementing secure authentication systems, comprehensive monitoring, and efficient caching strategies. 
Your work will involve building intelligent applications leveraging AI, designing data models for AI applications including vector storage and embeddings management, and developing comprehensive test suites with test-driven development (TDD) practices. 
This role requires 5+ years of backend development experience with strong expertise in microservices architecture, RESTful API design, and containerization technologies. You'll collaborate in an international environment requiring strong English communication skills, while having the opportunity to work with multiple LLM providers, orchestration frameworks, and cloud platforms (Azure, GCP, AWS). The position offers unique exposure to AI/ML model deployment, MLOps practices, and real-time data processing systems that power intelligent applications used by millions of users worldwide

Key Job Responsibilities
- Design and implement high-performance REST APIs, microservices, and event-driven architectures for AI applications 
- Develop intelligent applications leveraging AI with seamless switching and fallback mechanisms 
- Build AI service integration layers and implement complex workflows including Retrieval-Augmented Generation (RAG) and agent systems 
- Implement comprehensive monitoring, security, and testing strategies for production AI systems 
-Partner with cross-functional teams to translate AI product ideas into production-ready applications 

求める経験・スキル

Mandatory Qualifications: 
- Bachelor's degree or above in Computer Science, Software Engineering, or related technical discipline 
- 5+ years of backend development experience with scalable web applications and APIs 
- Strong expertise in Python, FastAPI, PostgreSQL, and Redis technologies 
- Strong English communication skills and experience with collaborative development workflows 
 
Desired Qualifications: 
- Experience with multiple LLM providers (OpenAI, Anthropic, Google Vertex AI) and frameworks like LangChain 
- Knowledge of vector databases, embedding management, and cloud platforms (Azure, GCP, AWS) 
- Experience with monitoring tools (Prometheus, Grafana) and AI/ML model deployment practices 
- Knowledge and understanding of distributed systems and security best practices