Career Opportunity for a Data Scientist in Japan! 

■ Data Scientist

■ Company Overview

An e-commerce, fintech, digital content and communications company with more than 30,000 employees, and operations in 30 countries and regions.

■ Your Role and Responsibilities 

Our vision is to empower our internal and external stakeholders by providing data driven marketing solutions by developing the Ad delivery, Audience Management, Tracking, Reporting and Data Platforms. You will be able to challenge yourself in a wide range of technologies in the frontline of heavy traffic large scale ad applications and platforms, including high performance system development and big data processing systems.

Position Detail

●Problem definition for ad delivery optimization and the design of KPIs/metrics, along with observability (dashboards and alerts).

●Data preprocessing, feature engineering, modeling, and offline evaluation (including simulation) for price optimization, CTR/CVR and value prediction, and creative optimization. 

●Online deployment and experiment design: A/B tests/bandits, calibration, rollout strategy planning, effectiveness evaluation, and continuous improvement.

●Production operations and MLOps: building training/inference pipelines; monitoring and drift detection; model updates and automated rollback; quality and privacy governance.

●Collaboration with internal stakeholders (product, engineering, sales/operations) on requirements definition, decision support, documentation, and knowledge sharing.

Development Environment

●Google Cloud Platform(GKE, Dataflow, Cloud Pub/Sub, BigQuery, Cloud SQL)

●Aerospike

●Terraform

●Ansible

●Python

●Go

Related systems, advertising products

●Ad Platform / DMP / Data feed / Tracking and reporting / Pixel tag

●Listing ads, Display ads, Video ads, and Google shopping ads

■ Experience and Qualifications

●3+ years of hands-on experience in data analysis and machine learning using Python and SQL; proficiency with Pandas/NumPy/scikit-learn and data visualization tools

●Experience processing large-scale data (e.g., Spark, BigQuery) and building reproducible analytics environments (using notebooks and repositories together, code reviews, testing)

●Solid foundation in statistics, probability, causal inference, and experimental design (hypothesis testing, sampling, A/B test design and analysis, effect size estimation)

●Experience developing machine learning models (regression, classification; tree-based methods/GBDT/logistic regression/simple neural networks) with rigorous evaluation design

●Foundational knowledge of online/digital advertising (CTR/CVR prediction, bidding and budget pacing, ad serving control, KPI optimization) or practical optimization experience in adjacent domains

●Feature engineering oriented toward price and serving optimization use cases; data quality management, leakage prevention, and handling delayed/late-arriving labels

●Production experience (model deployment, scheduling/pipeline operations, monitoring, implementing and operating drift detection)

■ Additional Preferred Qualifications
●Knowledge of ad auctions and mechanism design (first-price/second-price, bid shading, reserve price optimization, frequency control/capping)

●Hands-on experience applying price optimization methods (Bayesian optimization, multi-armed bandits, contextual bandits, reinforcement learning, etc.)

●Experience with creative optimization (multivariate testing, bandit optimization, image/text feature extraction, use of generative AI)

●Experience building serving-control models and simulations (e.g., budgeting, pacing, inventory forecasting)

●Experience implementing and operating streaming/real-time processing platforms (Kafka/Flink/Beam) and online (real-time) inference

●MLOps practices (feature stores, model registries, CI/CD, Docker/Kubernetes, monitoring/alerting, data drift/concept drift detection)

●Experience with cloud environments (GCP: BigQuery/Vertex AI/Dataflow, or equivalent services on AWS/Azure)

●Professional experience leveraging AI in real-world applications

■ Good Reasons to Join

● Hybrid position in Japan

● Work with International team members

●Language: Fluent Japanese speaker or have N2 Level of the Japanese Language Proficiency Test

■ Work Location

Tokyo, Japan

Details will be provided during the meeting.

Career Opportunity for a Senior Backend Engineer in Japan! 

■ Senior Backend Engineer 

■ Company Overview

A leading FinTech organization, cashless payments in Japan, offering innovative and convenient credit services integrated with a major digital payment platform.

■ Your Role and Responsibilities 

●We are looking for senior backend engineers to build, or rebuild, rock solid services with a laser focus on scalability and maintainability.

●(Re-)architect our systems landscape: we want to reassess and fix the behind-the-scenes to power a top-notch user experience. It is bundled with difficult design challenges to solve: we simply want to get it right.

●Design, support the implementation and deliver large scale, and complex, systems

●Manage teams stakeholders such as product managers or frontend engineers but also other team leads or non-tech stakeholders.

●Leverage the infrastructure to solve such large scale problems.

●Acts as a gatekeeper to the team quality standard

●Triage, debug and resolve product issues or other incoming inquiries

●Mentor other team members and saveguard the team quality standards

■ Experience and Qualifications

●5+ years equivalent experience in SaaS platform development.

●Experience in any OOP based language e.g Kotlin, Java, C#, Scala etc.

●Experience with RDBMS and NoSQL databases, along with distributed cache.

●Strong fundamentals in data structures, algorithms and object oriented programming.

●In-depth understanding of concurrency and distributed computing.

Back-end services:

Main implementations are in Spring Boot, with a mix of Java 11/Spring Boot 2 and Java

17/Spring Boot 3.

Some legacy systems are written in Java EE.

Testing is done with JUnit and Mockito

Deployment relies on AWS ECS

CI/CD is handled by AWS CodePipeline

Infrastructure

All our services run in AWS

Infrastructure is managed by AWS CloudFormation

AWS CloudWatch is used for observability

Coding environment: GitHub, IntelliJ, Gradle

Documentation & Project management: Confluence, Miro, JIRA

Communication: Slack, Zoom, Office 365

■ Additional Preferred Qualifications
●Experience with Java/Spring Boot framework

●Experience with implementing platform components such as RESTful APIs, Pub/Sub Systems, Database Clients.

●Experience in system design for high traffic application with scalability in mind

●Experience with microservices & event-driven architecture

●Experience gRPC communication design and implementation

●Experience in a multicultural environment

●Japanese conversational proficiency is a plus

■ Good Reasons to Join

● Hybrid work environment within Japan

● Work with International team members

■ Work Location

Tokyo, Japan

Details will be provided during the meeting.

Career Opportunity for a Cloud Infrastructure Engineer in Japan! 

■ Cloud Infrastructure Engineer (Native Japanese / JLPT N1 required)

■ Company Overview

A fintech company has grown rapidly and is widely used as a payment platform by about half of smartphone users in Japan. It also offers simple, everyday investment services through a mobile app, making asset management easy and accessible. As part of a larger group, the company is rapidly improving its products and driving the adoption of cashless payments and digital financial services in Japan. It is looking for professionals who are proactive, collaborative, and passionate about creating new value.

■ Your Role and Responsibilities 

Be part of the team to build up a new organization and environment. Develop skills in making business plans from a high perspective, through the high-level coordination with departments. Gain experience in a company that aiming to be the pioneer in the market to provide great services, which never had before during the era of Financial reformation

●Architect and build a robust, scalable and stable infrastructure

●Architect and build Infrastructure that is easily maintainable during patching and upgrades without downtime

●Architect and build Infrastructure with AWS regional level failure tolerance

●Work together with our Security Engineers to provision a secure Infrastructure

●Automations for AWS Deployments to ensure fast delivery of Cloud Services to our developers

●Provide through Automations means for developers to easily deploy resources on AWS

■ Experience and Qualifications

●5+ years of technical experience in AWS based Infrastructure solution design and build

●Experience in production level Infrastructure change management and releases for High traffic & business-critical systems

●Good understanding of Cloud security best practices and payment industry compliance standards

●Experience in production incident management and cross team collaboration

●Extensive technical hands-on experience of Computing, Storage and ●Analytical Services on Cloud(AWS)

●Experience with IAC tools in AWS such as Terraform etc.

●Experience with Linux Internals and System Administration

●Experience with Cloud Services Monitoring, Detection and Response

●Experience in Cloud Infrastructure Service patching and upgrades

■ Additional Preferred Qualifications
●Has maintained over 200 servers/containers in a production, customer facing cloud environment

●Experience in Disaster recovery for cloud systems and improvements for RTO and RPO

●Experience with other cloud service providers (e.g Google Cloud)

●Experience in Cloud Services Performance Tuning, cost controls and management

●Experience using and contributing to Open Source tools

●Published papers / blogs / articles - Experience in managing IT compliance and security risk

●Experience in working for infrastructure design and build in securities, finance, or similar industries

●Experience in in-house service operations

■ Good Reasons to Join

● Hybrid work model (flexible working style including Remote and office)

● Work with International team members

● Business level Japanese proficiency is required (JLPT N1 / Native)

■ Work Location

Tokyo, Japan

Details will be provided during the meeting.

Career Opportunity for a Java Software Engineer in Japan! 

■ Java Software Engineer (English speaking position)

■ Company Overview

An e-commerce, fintech, digital content and communications company with more than 30,000 employees, and operations in 30 countries and regions.

■ Your Role and Responsibilities 

Our systems power warehouse operations across Japan, enabling inventory management, receiving, shipping, fulfillment, delivery scheduling, shipment tracking, and customer notifications. We also support Super Logistics, providing logistics services for merchants and helping them deliver products efficiently to customers. As a software engineer, you’ll solve challenging distributed systems problems while building highly available backend services that support millions of customers and merchants across e-commerce platform.

Position Detail

●Build mission-critical systems that directly support one of Japan’s largest e-commerce platforms.

●Design and develop highly scalable backend services.

●Solve challenging distributed systems and performance problems.

●Work with modern cloud-native technologies.

●Influence technical design and architecture.

●Collaborate with experienced engineers across multiple platform teams.

●Take ownership of services from design through production operations.

<Responsibilities>

●Design, develop, and maintain scalable backend services using Java.

●Design reliable and highly available distributed systems.

●Improve system performance, scalability, and operational efficiency.

●Collaborate with platform and framework teams to improve developer productivity.

●Participate in architecture discussions and technical design reviews.

●Monitor production systems and contribute to incident response and continuous improvement.

●Write clean, maintainable, well-tested production code.

■ Experience and Qualifications

●More than 6 years of professional Java development experience.

●Deep expertise in Java, Micronaut, and modern backend development.

●Proven track record designing and delivering production-grade RESTful APIs and/or gRPC services

●Proven experience designing, building, and operating microservice architectures at scale.

<Distributed Systems>

●Proven production experience designing event-driven systems with Kafka, including partitioning strategies, consumer group management, and failure handling.

●Deep experience building and operating scalable, highly available distributed systems.

●Hands-on production experience with reactive programming (Reactor, RxJava, etc.)

<Infrastructure>

●Production experience deploying, scaling, and operating services on Kubernetes.

●Experience developing cloud-native applications on Kubernetes and private cloud platforms; AWS exposure is a plus.

●Experience with CI/CD pipelines and Git.

<Architecture & Design>

●Strong understanding of software architecture principles and design patterns.

●Experience leading technical design reviews and making architectural decisions.

<Data>

●Deep experience with relational and NoSQL databases (MySQL, Oracle, or Couchbase), including query optimization, schema design, and performance tuning.

●Experience with Redis for caching and session management.

<Development Environment>

●Java

●Kotlin 

●Micronaut

●Kubernetes

●Docker

●Kafka

●gRPC / Protocol Buffers

●REST APIs

●MySQL / Oracle / Couchbase

●Redis

●Gradle

●Git

●CI/CD (Jenkins)

●Elastic / Kibana

■ Additional Preferred Qualifications
●Experience working in Agile/Scrum teams.

●Experience with monitoring and observability tools such as Elastic/Kibana, Prometheus, or Grafana.

●Experience working on large-scale, high-traffic, mission-critical backend systems.

●Experience working in a globally distributed engineering team.

●Comfort working with AI-powered developer tools (coding assistants, internal chatbots, etc.)

■ Good Reasons to Join

● Hybrid position in Japan

● Work with International team members

●Language: No Japanese proficiency is required

■ Work Location

Tokyo, Japan

Details will be provided during the meeting.

Career Opportunity for a QA Automation Engineer in Japan! 

■ QA Automation Engineer (Business level English and Japanese proficiency required)

■ Company Overview

An e-commerce, fintech, digital content and communications company with more than 30,000 employees, and operations in 30 countries and regions.

■ Your Role and Responsibilities 

You will be responsible for providing a unified product strategy for the Business System that integrates the business potential. Our core missions are managing the product development lifecycle by focusing on building a platform, and enhancing AI-driven platform capabilities.

This position drives test automation for products in close collaboration with development teams, release management, and external partners.

Position Details

●Design and implement automated test solutions across web, app, API.

●Build and maintain scalable test frameworks that support continuous testing

●Collaborate with engineers and product teams to define quality requirements and acceptance criteria

●Drive integration of automated tests into CI/CD pipelines to enable continuous quality feedback

●Analyze test results, identify defects, and work with development teams to drive resolution

●Contribute to improving overall software quality through proactive testing strategies and expanded coverage

■ Experience and Qualifications

●7+ years of experience in software quality assurance with a focus on test automation

●Proficiency in at least one scripting or programming language

●Experience designing and implementing automated test frameworks

●Solid understanding of SDLC and QA methodologies

●Experience working in Agile development environments

●Strong analytical and problem-solving skills

■ Additional Preferred Qualifications
●Experience integrating automated tests into CI/CD pipelines

●Knowledge of API testing and backend system verification

●Knowledge of leveraging AI tools to enhance and accelerate test automation

■ Good Reasons to Join

● Hybrid position in Japan

● Work with International team members

●Language: Business level in both Japanese and English

■ Work Location

Tokyo, Japan

Details will be provided during the meeting.

JD Geniee 【JAPAN AI】Senior AI Consultant (マネージャー候補)

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