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Job ID : 1554604 Date Updated : August 10th, 2025
Engineer specializing in RAG in English

No Japanese Required AI Engineer (RAG Specialist)

Hiring Company AI company leading Japan AI market
Location Tokyo - 23 Wards, Shinjuku-ku
Job Type Permanent Full-time
Salary 7 million yen ~ 13 million yen

Work Style

Casual Clothing Minimal Overtime Flex Time

Job Description

Key Responsibilities

RAG System Design & Operation

  • Architect and implement RAG-based systems
  • Build and optimize vector databases (e.g., FAISS, Elasticsearch, Pinecone)
  • Develop document preprocessing and chunking strategies

Maintenance & Monitoring

  • Operate and monitor RAG systems in production
  • Analyze performance, identify bottlenecks, ensure stability

Accuracy Improvement

  • Evaluate and improve retrieval/response quality
  • Apply prompt engineering and model fine-tuning
  • Define and implement evaluation metrics

R&D and Technical Validation

  • Explore and validate cutting-edge RAG methods
  • Build POCs (Proof of Concept)
  • Contribute to architecture and tool decisions

Development

  • Build and extend RAG-related features
  • Design and implement APIs
  • Contribute to both frontend/backend development when needed

Team Structure

Our development team consists of approximately 65 members, structured into the following groups:

  • Client-Facing Solution Development
  • In-house AI SaaS Development
  • Common Platform Development (Infra / Data / AI R&D)

General Requirements

Minimum Experience Level Over 6 years
Career Level Mid Career
Minimum English Level Business Level (Amount Used: English Only)
Minimum Japanese Level None
Minimum Education Level Bachelor's Degree
Visa Status Permission to work in Japan required

Required Skills

Minimum Qualifications

  • Bachelor’s degree or equivalent experience in CS, AI, ML, Mathematics, or related fields
  • Hands-on experience designing, building, and operating RAG systems
  • Experience with vector DBs (e.g., FAISS, Elasticsearch, Pinecone)
  • Document preprocessing and chunking strategies
  • Production monitoring and incident response
  • System optimization and performance tuning
  • Evaluation and improvement of search/generation quality
  • Prompt engineering & fine-tuning
  • Metric design and implementation
  • API development (e.g., RESTful APIs)
  • Python development (including ML/NLP libraries)
  • Experience with cloud (AWS, GCP, etc.)
  • Team collaboration and communication skills
  • English: Business level or above

Preferred Qualifications

  • Frontend/backend experience (React, Vue.js, Flask, FastAPI, etc.)
  • LLM tuning and evaluation experience
  • CI/CD experience (GitHub Actions, Jenkins)
  • Containerization (Docker, Kubernetes)
  • Familiarity with RAG-related academic papers and trends
  • POC development experience
  • Data engineering knowledge (ETL, pipelines)
  • Strong reading skills of English technical documents

Tech Stack / Tools

  • Languages: Python (Backend), TypeScript / React / Next.js (Frontend) / NX
  • Infrastructure: GCP (Kubernetes), Docker
  • Tools: Slack, Confluence, Linear, Google Workspace, GitHub, Notion
  • Hardware: Mac (Apple Silicon), dual monitors

Job Location

  • Tokyo - 23 Wards, Shinjuku-ku

Work Conditions

Job Type Permanent Full-time
Salary 7 million yen ~ 13 million yen
Industry Internet, Web Services

Job Category

  • IT, Web and Communication > Web Developer
  • IT, Web and Communication > Software Developer
  • IT, Web and Communication > AI Specialist, Data Scientist

Company Details

Company Type Large Company (more than 300 employees)
Non-Japanese Ratio About half Japanese