【React × Python × Generative AI】Full-Stack Engineer｜Remote & Full Flex｜¥7M–11M

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▶︎ Work Style & Location

💰 Annual Salary: ¥7M–11M

🏠 Remote Work Available – Flexible choice between home and Tokyo office

⏰ Full Flex-Time – No core hours (7:00 AM–10:00 PM)

🤖 Generative AI × LLM × RAG × Secure Computing

🌍 International Engineering Team

🏖️ 125+ Annual Holidays

🇯🇵 Japanese N1-equivalent & Business English Required

▶︎ About the Company

An innovative, fast-growing AI technology startup based in Tokyo, developing next-generation enterprise AI solutions that enable organizations to securely utilize sensitive data and unlock its business value.

The company specializes in Generative AI, Large Language Models (LLMs), privacy-preserving technologies, and secure data platforms, helping major enterprises accelerate digital transformation while maintaining high standards of data security.

With award-winning technologies, established enterprise partnerships, and a rapidly expanding engineering team, the company offers an exciting opportunity to build advanced AI-powered products in a modern, international environment.

Engineers have the opportunity to work directly with AI and security specialists, combining cutting-edge research with real-world product development.

▶︎ Role Overview

We are seeking an experienced Full-Stack Engineer to design, develop, and scale next-generation AI-powered web applications and secure enterprise platforms.

You will work across both frontend and backend development using React, TypeScript, Python, and FastAPI, while contributing to advanced Generative AI applications, LLM/RAG systems, and cloud-native infrastructure.

This is an excellent opportunity for engineers who want to go beyond traditional web development and gain hands-on experience with AI, modern cloud architecture, and privacy-preserving technologies.

Depending on the project, you may work on proprietary SaaS products or enterprise-focused development projects.

▶︎ Key Responsibilities

Design, develop, and maintain full-stack web applications using React, TypeScript, Python, and FastAPI

Build scalable backend APIs and modern frontend interfaces

Develop data models and search infrastructure using PostgreSQL, Qdrant, and OpenSearch

Design and operate LLM/RAG systems using OpenAI and Azure OpenAI

Contribute to privacy-preserving AI and secure computing solutions

Develop and operate cloud-native microservices using AWS, Docker, and Kubernetes

Improve CI/CD pipelines using GitHub Actions and Terraform

Conduct code reviews, automated testing, and performance monitoring

Collaborate with AI researchers, engineers, and enterprise clients

▶︎ Required Skills & Experience

5+ years of professional web application development experience covering frontend and backend

Hands-on experience with React, TypeScript, or similar SPA frameworks

Experience developing backend APIs using Python frameworks such as FastAPI

Experience with relational databases such as PostgreSQL

Practical experience with Docker containers

Experience with Git/GitHub in collaborative development environments

Experience developing applications on AWS (EKS, ECS, RDS, Lambda, etc.)

Experience communicating proactively with clients

Business-level Japanese (N1 equivalent or above)

Business-level English

▶︎ Preferred Skills

Kubernetes and microservices architecture

Vector databases such as Qdrant

Full-text search technologies such as OpenSearch

LLM/RAG application development

Graph database technologies

Privacy-preserving machine learning or homomorphic encryption

CI/CD pipeline implementation

Experience with enterprise SaaS products

Interest in Generative AI and emerging technologies

▶︎ Tech Stack

Frontend: React, TypeScript, Vue.js

Backend: Python, FastAPI, Flask

Databases: PostgreSQL, Qdrant, Redis

Search: OpenSearch

Cloud & Infrastructure: AWS, Azure, Docker, Kubernetes, Terraform

AI / ML: OpenAI, Azure OpenAI, Hugging Face, Transformers, RAG

CI/CD: GitHub Actions, Argo CD

▶︎ Compensation & Benefits

💰 Annual Salary: ¥7M–11M (Negotiable based on experience and skills)

Remote work and flexible office attendance

Full flex-time system without core hours

Monthly learning and book allowance up to ¥5,000

Seminar participation and certification support

Visa application and renewal support for international employees

Comprehensive social insurance

Annual health checkups

Transportation allowance up to ¥50,000/month

Welcome lunches, team gatherings, and company events

▶︎ Work Location

Tokyo, Japan (Remote Work Available)

Employees can flexibly choose between working remotely and attending the Tokyo office, subject to initial manager consultation.

Occasional office attendance or meetings with clients in the Tokyo area may be required.

▶︎ Holidays & Leave

125+ annual holidays

Weekends and Japanese national holidays

Annual paid leave (granted after 3 months)

3 days of summer vacation (subject to eligibility)

New Year holidays

Anniversary leave (1 additional day annually)

Up to 5 days of special sick leave for employees or family members

Maternity and childcare leave

Bereavement and other special leave