AI Engineer

A Global IT Service firm is seeking an AI Engineer to join the AI & Data Division. In this role, you will be embedded directly within one of the business unit engineering teams and work hands-on to drive the adoption of AI and open-source large language models hosted within the environment.

You will collaborate closely with product and engineering teams to build, deploy, evaluate, and optimize LLM-powered features and agent workflows in production.

This position is ideal for engineers who enjoy building real-world AI applications, solving practical business problems with LLMs, and taking solutions from prototype to production.

Responsibilities:

- Embed inside a business unit’s engineering team and implement agent and tool-use workflows for their use case, including function calling, multi-step flows, retrieval, guardrails, and fallback handling, writing production code in their codebase

- Get features from prototype into production and support them there, including debugging failures, tightening latency and cost, and fixing what breaks

- Run task-level evaluations of in-house and open-source models for your use case, and extend and maintain the evaluation sets and harnesses together with the business unit

- Design and iterate prompts, output schemas, and tool definitions, versioned and measured against evaluations rather than tuned by feel, and help narrow quality problems down to the prompt, retrieval system, model, or data

- Support migrations from third-party APIs to our in-house models, and surface gaps and findings to the senior engineer on the engagement as well as to model and platform teams

- Document successful approaches as reusable recipes, examples, and starter templates for the team’s shared library, and help business unit engineers adopt our tools and APIs

Required Skills:

- 3 to 6 years of professional software engineering experience, including hands-on work building LLM applications

- Practical agentic engineering experience. You have built agents using tool and function calling or an orchestration framework and have debugged them when they misbehave

- Working knowledge of prompt engineering, including structured outputs, iteration against test cases, and an understanding that prompts require versioning and measurement

- Strong fundamentals in at least one modern programming language (e.g., Python, Java, or Go), and comfort with APIs, backend services, and testing

- Curiosity about how models behave. You want to understand why an output was wrong, not just retry it

- Comfortable working embedded within another engineering team, communicating directly with business stakeholders, and operating effectively in ambiguous environments

What you should apply:

- Build and deploy real-world AI applications using AI and open-source LLMs at production scale

- Work directly with diverse business units across e-commerce, fintech, digital content, and communications to drive meaningful business impact

- Gain hands-on experience with agentic workflows, prompt engineering, model evaluation, RAG, and LLM operations

- Collaborate with experienced AI engineers and platform teams while taking ownership of end-to-end solution delivery

- Play a key role in accelerating the enterprise-wide adoption of in-house and open-source AI technologies

Company Overview:

This is a global company with a strong presence in multiple business sectors. It has achieved sustained growth both domestically and internationally, including in the U.S. and Europe. The company prides itself on its diverse and international environment, providing ample career opportunities and a commitment to equal opportunity. With a wide range of business activities, the company also works with various technologies. You can choose your preferred working environment, whether Windows or Mac! Meals at the employee cafeteria are free, and the chef regularly comes up with new menus, ensuring you never get bored of the meals!

Salary: 8,000,000 JPY ~ 10,000,000 JPY (Depend on experience, Inc. Bonus) + Stock Options

Work Hours: 9:00 AM – 5:30 PM (Flextime or staggered working hours possible)

Work Style: Hybrid (Typically 4 days in the office, 1 day working from home)

Holidays: Saturdays, Sundays, public holidays, New Year holidays, paid leave, bereavement leave, and other special leave

Benefits: Full social insurance (employee pension insurance, health insurance, worker’s accident compensation insurance, unemployment insurance), DC pension plan, transportation allowance, childcare and caregiving support, cafeteria, retirement benefit system, welfare services (Relo Club), health counseling services, relocation support (visa support, moving), employee discounts (moving, language classes, etc.), and more

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