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Project Lion - Senior Prompt Engineer - Japan (Remote, Part-Time)

1 week, 4 days ago
Japan
Freelance
Senior
Prompt Engineer
Data Science and Analytics
LLM NLP SQL
Apply Now
Welo Global

Welo Global

Welo Global specializes in providing enterprise localization, AI training data, and multilingual content solutions, leveraging a portfolio of specialized global brands to meet diverse customer needs in the AI and language services industry.

Professional Services
Founded 1997
View All Jobs 402

Description

  • Lead the end-to-end technical migration workflow for transitioning templates to LLM autoraters.
  • Use internal tools to generate baseline prompts for complex parent-child template clusters.
  • Run and supervise automated prompt optimization workflows, reviewing outputs and identifying deadlocks or plateaus.
  • Manually draft, test, and refine prompts for complex template architectures and edge cases.
  • Overcome prompt anti-patterns and resolve scenarios where tooling is missing or broken.
  • Monitor shadowbot runs to ensure disagreements between human and LLM ratings are generated and tracked.
  • Run prompt versions against gold data to measure autorater quality against the human crowd baseline.
  • Calculate evaluation metrics such as F1 score, precision, and recall.
  • Draft launch readiness justification and certification documentation for final release.

Requirements

  • Native fluency in Japanese and fluent English.
  • Must be based in Japan.
  • Bachelor's, Master's, or Doctorate degree in Computer Science, Data Science, Computational Linguistics, Human-Computer Interaction, Cognitive Science, or a related analytical field.
  • At least 4 years of experience as a Prompt Engineer.
  • Proven experience tuning LLMs for strict, structured outputs and complex classification tasks.
  • Familiarity with chain-of-thought prompting and few-shot learning.
  • Strong proficiency in identifying error patterns, analyzing model performance, and using SQL or other data analytics tools.
  • Ability to quickly learn and master proprietary tools with minimal supervision.
  • Excellent verbal and written communication skills.
  • Preferred: Familiarity with enterprise-grade LLM interfaces such as the Goose API.
  • Preferred: Experience in AI model evaluation, data science, computational linguistics, or software engineering.
  • Preferred: Hands-on experience with Automated Prompt Optimization (APO) systems or tuning workflows.
  • Preferred: Linguistic expertise, including understanding of semantics and logic.

Interested in this position?

Apply directly on the company website

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