Senior AI Engineer

**About the company:** Treasure AI Minato-ku, Tokyo Treasure AI is the only enterprise Customer Data Platform that harmonizes an organization’s data, insights, and engagement technology stacks to drive relevant, real-time customer experiences throughout the entire customer journey. **Responsibilities:** Lead the design and implementation of AI-powered features: LLM integrations, retrieval-augmented generation, agentic pipelines, and AI-augmented workflows Own prompt engineering rigor — structure prompts systematically, evaluate outputs, iterate based on production signal, and document what works Develop LLM integration patterns for the pod: streaming responses, function calling, context window management, fallback handling, and evaluation Understand the AI solution space well enough to recommend the right approach — knowing when to reach for prompting, RAG, fine-tuning, or agentic patterns, and when to bring in additional expertise Contribute production-grade code in Ruby/Rails and TypeScript/React; hold a high bar for code quality in AI and non-AI features alike Use Claude Code and GitHub Copilot fluently; critically review AI-generated code and help teammates do the same Work with our customer-facing agent platform to build, iterate, and deploy AI capabilities Independently scope AI feature work within the team’s 3-week delivery cadence, accounting for experimentation cycles and evaluation needs Own on-call shifts; develop operational instincts for AI systems in production — including latency, cost at scale, multi-tenant routing, and customer data boundaries Ship AI features iteratively — deliver a working version early and refine based on real usage Conduct deep code reviews on AI feature work; help teammates reason about model behavior, prompt design, and integration robustness Share LLM integration knowledge across the pod and contribute to cross-pod AI engineering discussions Help peers grow their AI engineering skills through pairing, documentation, and structured feedback Champion shared ownership of AI systems — avoid knowledge silos around model behavior and integration details Requirements 4–7 years of software engineering experience with significant focus on AI/ML features or LLM-powered product development Strong proficiency in prompt engineering, LLM API integration, and building AI features that perform reliably in production Experience with RAG, agentic workflows, or function-calling/tool-use patterns with language models Experience making AI solution tradeoffs in production — choosing between prompting, RAG, fine-tuning, and agentic approaches based on real constraints Solid full-stack skills in Ruby/Rails and TypeScript/React Fluency with Claude Code, GitHub Copilot, and our customer-facing agent platform Experience evaluating LLM outputs systematically — evals, test cases, production monitoring Operational awareness of AI systems in production: latency management, cost at scale, multi-tenant routing, and customer data boundaries Track record of meaningful code reviews that grow teammates’ technical capabilities Compensation ¥10,000,000 ~ ¥14,000,000 annually. APPLY FOR THIS POSITION DO YOU NEED MORE INFO? ASK A QUESTION About Treasure AI Treasure AI Minato-ku, Tokyo Treasure AI is the only enterprise Customer Data Platform that harmonizes an organization’s data, insights, and engagement technology stacks to drive relevant, real-time customer experiences throughout the entire customer journey. Key benefits Highly Technical Founders Globally distributed company Open Source is in our DNA Read more More jobs like this We'll send you a digest of new English-friendly software developer jobs in Japan. Your email stays private, we don't share or sell it. Apply for this position × This position is only open to current residents of Japan. I have a favour to ask. When you apply to Treasure AI, please tell them that you heard about the position on TokyoDev . This helps to keep this job board sustainable, so I'd be grateful for your support with this. - Paul, Founder of TokyoDev Continue applying © 2026 Privacy Policy **Requirements:** 4–7 years of software engineering experience with significant focus on AI/ML features or LLM-powered product development Strong proficiency in prompt engineering, LLM API integration, and building AI features that perform reliably in production Experience with RAG, agentic workflows, or function-calling/tool-use patterns with language models Experience making AI solution tradeoffs in production — choosing between prompting, RAG, fine-tuning, and agentic approaches based on real constraints Solid full-stack skills in Ruby/Rails and TypeScript/React Fluency with Claude Code, GitHub Copilot, and our customer-facing agent platform Experience evaluating LLM outputs systematically — evals, test cases, production monitoring Operational awareness of AI systems in production: latency management, cost at scale, multi-tenant routing, and customer data boundaries Track record of meaningful code reviews that grow teammates’ technical capabilities Compensation ¥10,000,000 ~ ¥14,000,000 annually. APPLY FOR THIS POSITION DO YOU NEED MORE INFO? ASK A QUESTION About Treasure AI Treasure AI Minato-ku, Tokyo Treasure AI is the only enterprise Customer Data Platform that harmonizes an organization’s data, insights, and engagement technology stacks to drive relevant, real-time customer experiences throughout the entire customer journey. Key benefits Highly Technical Founders Globally distributed company Open Source is in our DNA Read more More jobs like this We'll send you a digest of new English-friendly software developer jobs in Japan. Your email stays private, we don't share or sell it. Apply for this position × This position is only open to current residents of Japan. I have a favour to ask. When you apply to Treasure AI, please tell them that you heard about the position on TokyoDev . This helps to keep this job board sustainable, so I'd be grateful for your support with this. - Paul, Founder of TokyoDev Continue applying © 2026 Privacy Policy **Compensation:** ¥10,000,000 ~ ¥14,000,000 annually. APPLY FOR THIS POSITION DO YOU NEED MORE INFO? ASK A QUESTION About Treasure AI Treasure AI Minato-ku, Tokyo Treasure AI is the only enterprise Customer Data Platform that harmonizes an organization’s data, insights, and engagement technology stacks to drive relevant, real-time customer experiences throughout the entire customer journey. Key benefits Highly Technical Founders Globally distributed company Open Source is in our DNA Read more More jobs like this We'll send you a digest of new English-friendly software developer jobs in Japan. Your email stays private, we don't share or sell it. Apply for this position × This position is only open to current residents of Japan. I have a favour to ask. When you apply to Treasure AI, please tell them that you heard about the position on TokyoDev . This helps to keep this job board sustainable, so I'd be grateful for your support with this. - Paul, Founder of TokyoDev Continue applying © 2026 Privacy Policy