Backend Jobs in Tokyo, Tōkyō

Add your latest CV to match with open positions

Head of Development

Tokyo,
remote
Permanent
20.0M - 30.0M JPY / Yearly
Company Profile Construction AI company building an AI-native quantity-takeoff system, adopted by major general contractors and building materials manufacturers, is looking for a staff engineer to lead its full-stack AI platform. The Role <ul><li>You will coordinate the AI, frontend and backend teams to deploy multi-model AI pipelines (vision-language, OCR, segmentation, object detection) into production.</li><li>You will deliver interactive web canvases (2D/2.5D) that let industry experts inspect and edit AI results in real time.</li><li>You will drive domain architecture for a multi-tenant enterprise data model (MDM, CPQ, quantity takeoff) and optimize model serving to achieve sub-second multi-model execution.</li><li>You will raise the engineering bar across the team (schema migration, evaluation harnesses) and translate client and PM needs into technical roadmaps.</li></ul> Your Skills <ul><li>Fluent or native level Japanese</li><li>You have one or two of the strengths below:</li></ul><ol><li>Hands-on experience deploying AI models to production alongside AI research/engineering teams.</li><li>Track record of designing sophisticated software systems and aligning frontend and backend engineers.</li><li>Experience leading engineering teams and cross-functional units, including working with PMs and external clients.</li><li>Experience with CAD/BIM or spatial data, ERP/CPQ integrations, CUDA/C++, vLLM/llama.cpp, or distributed multi-time-zone teams is a plus.</li></ol> Key Highlights of the Role <ul><li>Work on proprietary in-house AI models that outperform commercial frontier models, not "wrapper" products.</li><li>Join a small, elite team with real ownership and autonomy.</li><li>Be part of a fast-growing company expanding globally</li><li>Shape the future of construction through the world's first product of its kind, originating from Tokyo.</li></ul> Location Tokyo Salary20 - 30 million yen Reference Number: 06940-0013517591 By clicking 'apply', you are deemed to have agreed to Robert Half Japan Privacy Notice (<a href="https://www.roberthalf.com/jp/en/privacy">https://www.roberthalf.com/jp/en/privacy</a>). Please ensure that your application documents do not include sensitive personal data such as race, beliefs, medical history, criminal record, or other information irrelevant to hiring process such as spouse or dependents. All information must be accurate and truthful, and any included hyperlinks must be safe and secure.<img src="https://counter.adcourier.com/TmFuY3kuWXVhbi4xMzQ1NS4xMDg5OEByaGlqcC5hcGxpdHJhay5jb20.gif">
2026-10-01T06:06:31Z

Software Engineer

Tokyo,
remote
Contract
16.9M - 16.9M JPY / Yearly
Company ProfileA venture-backed AI technology company focused on developing verifiable and explainable AI solutions for scientific and engineering applications. The company combines advanced machine learning, formal reasoning, and domain expertise to accelerate innovation in complex technical fields, including engineering design, semiconductors, and scientific research. The Role<ul><li>Develop and maintain backend applications using Python/FastAPI and frontend applications using React/Next.js</li><li>Design APIs and databases, and optimize SQL performance</li><li>Contribute to system architecture and technical decision-making</li><li>Build scalable, secure, and reliable systems</li><li>Develop and enhance AI-powered features and agent workflows</li><li>Integrate and utilize LLM technologies and AI platforms</li><li>Perform unit, integration, and end-to-end testing</li><li>Participate in code reviews and quality improvement initiatives</li><li>Collaborate closely with Tech Leads and AI Engineers</li><li>Support cross-functional development teams and knowledge sharing</li></ul> Your Skills <ul><li>Cloud platforms and infrastructure</li><li>AI/LLM integration (OpenAI, Anthropic, Vertex AI, etc.)</li><li>Testing (Unit, Integration, E2E)</li><li>System design and scalable architecture</li><li>CI/CD and software engineering best practices</li><li>Troubleshooting and production support</li></ul> Key Highlights of the Role <ul><li>Work on next-generation AI products for science and engineering.</li><li>Build both full-stack applications and AI-powered features.</li><li>Influence system architecture and technical strategy.</li></ul> Salary8,125 JPY　〜 hourly Reference Number: 06940-0013502812 By clicking 'apply', you are deemed to have agreed to Robert Half Japan Privacy Notice (<a href="https://www.roberthalf.com/jp/en/privacy">https://www.roberthalf.com/jp/en/privacy</a>). Please ensure that your application documents do not include sensitive personal data such as race, beliefs, medical history, criminal record, or other information irrelevant to hiring process such as spouse or dependents. All information must be accurate and truthful, and any included hyperlinks must be safe and secure.<img src="https://counter.adcourier.com/bWljaGFlbC5oYWdlZG9ybi45MjQ2Ni4xMDg5OEByaGlqcC5hcGxpdHJhay5jb20.gif">
2026-10-02T03:30:41Z

Engineering Manager

Tokyo,
remote
Permanent
15.0M - 15.0M JPY / Yearly
Company Profile<div>A fast-growing global technology company is seeking an Engineering Manager to lead a Core Services team responsible for building and operating the foundational platform capabilities that power mission-critical products used by enterprise customers worldwide.</div> The Role<ul><li>Lead and mentor a team of software engineers.</li><li>Drive high-quality delivery of platform and engineering initiatives.</li><li>Establish effective processes, planning, and team accountability.</li><li>Support architecture discussions and key technical decisions.</li><li>Balance scalability, reliability, and long-term maintainability.</li><li>Partner with cross-functional stakeholders to execute business priorities.</li><li>Foster a collaborative and high-performing engineering culture.</li><li>Act as an escalation point for critical incidents and operational issues.</li><li>Continuously improve engineering standards and team performance.</li></ul> Your Skills <ul><li>Native-level Japanese and business-level English.</li><li>8+ years of software engineering experience.</li><li>3+ years of engineering leadership experience.</li><li>Strong architectural and technical decision-making skills.</li><li>Solid knowledge of backend systems, APIs, and distributed platforms.</li><li>Proven experience developing high-performing teams.</li><li>Ability to drive impactful delivery and business outcomes.</li><li>Experience collaborating with distributed teams and stakeholders.</li><li>Strong communication and execution capabilities.</li></ul> Key Highlights of the Role <ul><li>Take ownership of a mission-critical platform that supports globally utilized products and services.</li><li>Lead a talented engineering team and play a key role in its growth and development.</li><li>Influence architectural decisions and contribute to long-term technology strategy.</li><li>Work in a highly collaborative, international environment with strong leadership exposure.</li></ul> Location Tokyo Salary15 million yen - Reference Number: 06940-0013501948 By clicking 'apply', you are deemed to have agreed to Robert Half Japan Privacy Notice (<a href="https://www.roberthalf.com/jp/en/privacy">https://www.roberthalf.com/jp/en/privacy</a>). Please ensure that your application documents do not include sensitive personal data such as race, beliefs, medical history, criminal record, or other information irrelevant to hiring process such as spouse or dependents. All information must be accurate and truthful, and any included hyperlinks must be safe and secure.<img src="https://counter.adcourier.com/c3VlLnRpbmcuNzYyMzUuMTA4OThAcmhpanAuYXBsaXRyYWsuY29t.gif">
2026-10-01T07:20:38Z

Bilingual Machine Learning Engineer

Tokyo,
remote
Permanent
7.0M - 13.0M JPY / Yearly
Company ProfileA pioneer in Japan's Expert Network Services (ENS) industry, providing highly accurate knowledge matching across regions and language barriers for consulting firms and financial institutions, is looking for a Machine Learning Engineer to join its Tokyo office. The Role<ul><li>Lead the design and implementation of autonomous AI agents using predictive and generative models, working closely with English-speaking engineering teams based in the US and Europe.</li><li>Drive Japanese NLP and accuracy evaluation efforts - from preprocessing and chunking strategies to building systems that evaluate the accuracy of Japanese data.</li><li>Select and evaluate LLMs across multiple providers (OpenAI, Anthropic, Google, etc.), balancing cost optimization with system robustness.</li><li>Build CI/CD pipelines and institutionalize best practices around model training, monitoring, and version control (MLOps).</li><li>Optimize inference performance and scalability of machine learning models, and fine-tune LLMs for domain-specific use cases.</li><li>Join around 2-3 early-morning or evening online meetings per week to coordinate with overseas teams.</li></ul> Your Skills <ul><li>At least 3 years of practical ML and backend development experience, with the ability to independently understand and develop large-scale Python codebases.</li><li>Core hands-on experience in at least one of: LLM orchestration (structured outputs, tool use, agent workflows), ML pipelines with tabular data (feature engineering, ranking models/LTR, model evaluation), or modern DevOps/MLOps environments (Docker, pytest, CI/CD).</li><li>Bachelor's or master's degree in computer science, data science, mathematics, statistics, or equivalent experience.</li><li>Business-level English proficiency is required; everyday-conversation-level Japanese is a plus.</li><li>Public cloud development experience and experience growing a service in collaboration with non-engineers are advantageous.</li></ul> Key Highlights of the Role <ul><li>Directly shape the AI-driven transformation of a company's core "search and matching" business, backed by an 800,000-person expert network and billions of yen in revenue.</li><li>Own projects end-to-end, from problem definition and spec development through release and iteration, in an environment where your ideas carry real weight.</li><li>Build your career with an international outlook, collaborating across multi-site development hubs in Tokyo, the US, and the EU - with the option to work from the New York office.</li><li>Work with a modern AI/ML stack (Azure OpenAI, LangChain, LangGraph, Transformers) on high-impact, production-facing generative AI features.</li></ul> Location Tokyo Salary7 - 13 million yen Reference Number: 06940-0013481561 By clicking 'apply', you are deemed to have agreed to Robert Half Japan Privacy Notice (<a href="https://www.roberthalf.com/jp/en/privacy">https://www.roberthalf.com/jp/en/privacy</a>). Please ensure that your application documents do not include sensitive personal data such as race, beliefs, medical history, criminal record, or other information irrelevant to hiring process such as spouse or dependents. All information must be accurate and truthful, and any included hyperlinks must be safe and secure. <img src="https://counter.adcourier.com/U21haWwuU2FmaS4xMDY3NC4xMDg5OEByaGlqcC5hcGxpdHJhay5jb20.gif">
2026-08-03T06:57:38Z

Data Scientist - ML/AI

Tokyo,
remote
Permanent
9.0M - 14.0M JPY / Yearly
Company ProfileA major Japanese internet services conglomerate is hiring a Senior Data Scientist for its global ad technology division. The division runs the advertising systems behind the group's e-commerce and digital services, with a diverse team spread across Japan, Singapore, India, China, and the UK. The Role<ul><li>The in-house ad serving platform handles tens of thousands of QPS at under 100ms latency and processes tens of billions of log records each month. It is now strengthening the in-house development of its core algorithms to set itself apart in a competitive, AI-driven market.</li><li>You will drive ad delivery optimization end to end, from problem definition and KPI design through modeling, online deployment, evaluation, and continuous improvement.</li><li>Your focus will be on price optimization, CTR/CVR and value prediction, and creative optimization, including feature engineering and offline evaluation and simulation.</li><li>You will design A/B tests and bandit experiments, plan rollouts, and build MLOps pipelines with monitoring, drift detection, and automated rollback.</li><li>You will join a team of about 20 engineers (SRE, backend/frontend, data, SDK, QA) and work closely with product, engineering, and sales/operations stakeholders.</li></ul> Your Skills Mandatory<ul><li>5+ years of hands-on data analysis and machine learning experience with Python and SQL (Pandas, NumPy, scikit-learn)</li><li>Experience processing large-scale data (e.g., Spark, BigQuery) and building reproducible analytics environments</li><li>A strong foundation in statistics, causal inference, and experimental design, including A/B test design and analysis</li><li>Experience developing ML models (GBDT, logistic regression, simple neural networks) with rigorous offline/online evaluation and calibration</li><li>Knowledge of digital advertising (CTR/CVR prediction, bidding, budget pacing), or optimization experience in an adjacent domain</li><li>Production experience with model deployment, pipeline operations, monitoring, and drift detection</li><li>A degree in computer science, statistics, applied mathematics, or a related field, or equivalent practical experience</li><li>Fluent English, or TOEIC 800+ or equivalent</li></ul> Desired<ul><li>Knowledge of ad auctions and mechanism design (first-/second-price auctions, bid shading, reserve price optimization)</li><li>Hands-on experience with price optimization methods such as Bayesian optimization, contextual bandits, or reinforcement learning</li><li>Experience with creative optimization, streaming platforms (Kafka/Flink/Beam), and real-time inference</li><li>MLOps practices (feature stores, CI/CD, Docker/Kubernetes) and GCP experience (BigQuery, Vertex AI, Dataflow)</li><li>Business-level Japanese (JLPT N2 or equivalent)</li></ul> Key Highlights of the Role <ul><li>Build the core algorithms of a large-scale ad platform used across one of Japan's largest internet ecosystems.</li><li>Take ownership of the full ML lifecycle, from hypothesis to production, with real business impact.</li><li>Work hands-on with high-traffic, low-latency systems and big data on a modern GCP stack.</li><li>Collaborate in a multinational team across five countries and work alongside leading external ad platforms.</li></ul> Location Tokyo Salary9 - 14 million yen Reference Number: 06940-0013531637 By clicking 'apply', you are deemed to have agreed to Robert Half Japan Privacy Notice (<a href="https://www.roberthalf.com/jp/en/privacy">https://www.roberthalf.com/jp/en/privacy</a>). Please ensure that your application documents do not include sensitive personal data such as race, beliefs, medical history, criminal record, or other information irrelevant to hiring process such as spouse or dependents. All information must be accurate and truthful, and any included hyperlinks must be safe and secure.<img src="https://counter.adcourier.com/U21haWwuU2FmaS41MTE5MS4xMDg5OEByaGlqcC5hcGxpdHJhay5jb20.gif">
2026-10-26T02:19:29Z

5 results for Backend in Tokyo, Tōkyō