Software Engineer (Generative AI)

Salary (published): ¥8,000,000–¥12,500,000 / year (base ¥534,000–¥834,000 / month incl. 35h fixed overtime). Languages: English proficiency required — Japanese is not required.

About the role

Apply LLMs across LINE Yahoo’s consumer services — Yahoo! Maps, CarNavi, Chiebukuro — in the Local / UGC domain, from prompt engineering through LLMOps and evaluation.

Responsibilities

• Apply LLMs across LINE Yahoo services (Yahoo! Maps, CarNavi, Chiebukuro)
• Prompt engineering
• LLMOps — model operation and improvement
• Build automated evaluation frameworks
• Generative-AI model design and optimization

Qualifications

• CS background or equivalent; algorithms and data structures
• 3+ years of web/server development on Linux
• Internal LLM-application experience
• Security-risk awareness for AI/LLM

Nice to have

• Generative-AI service development
• LLM mechanisms (Tool Calling, Deep Research)
• Data design and collection
• ML/LLM security

Tech stack

LLMs, prompt engineering, LLMOps, GitHub Copilot Agent, Claude Code.

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External listing — the salary range is stated on the official posting (verified live 2026-07-30). The Apply button takes you to the official LY Corporation careers page.