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

Role overview

Qualifications

  • Native fluency in Japanese and fluent in English
  • Bachelor’s, Master’s, or Doctorate degree in Computer Science, Data Science, Computational Linguistics, Human-Computer Interaction (HCI), Cognitive Science, or a related analytical field
  • At least 4 years' experience as Prompt Engineer
  • Strong proficiency in identifying error patterns, analyzing model performance, and using SQL or other data analytics tools

Responsibilities

  • Utilize Automatic Prompt Generation (APG) tools to create baseline prompts for complex parent-child template clusters
  • Run and supervise Automated Prompt Optimization (APO) tool, review outputs, and flag deadlocks or plateaus
  • Manually draft, test, and refine prompts to navigate complex template architectures and handle edge cases
  • Monitor shadowbot runs to ensure sufficient disagreements between human and LLM ratings

Key facts

  • Remote from: Japan
  • Freelance
  • Senior (5-10 years)
  • 0
  • English, Japanese

Other skills

  • Mental Agility
  • Communication

About the company

Welo Global logo

Welo Global

Welo Global is a leader in multilingual AI, technology, and content solutions serving over 2,000 clients in 300 languages. The company combines globally scaled multilingual infrastructure, including a network of over 500,000 linguists and domain experts, with advanced NLP, computational linguistics, and best-in-class compliance backed by seven ISO certifications. Welo Global’s five brands—Welocalize (multilingual content and localization solutions for localization and technology teams), Adapt (multilingual performance-led digital marketing agency), Park IP (patent translation, foreign filing, and legal solutions for law firms and corporate legal teams), Welo Life Sciences (multilingual content solutions for drug and medical device development for pharmaceutical, clinical contract research, and medical device organizations), and Welo Data (multilingual data generation, evaluation, and human data infrastructure for AI systems)—serve distinct customer segments with purpose-built expertise, fit-for-purpose solutions, and supporting technology. weloglobal.com

Company details

Company size1001 - 5000

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Job description

 We are seeking a Prompt Engineer to be responsible for the end-to-end technical migration workflow for transitioning templates to LLM autoraters. The role is required to use client’s internal tools to leverage prompt engineering techniques to maximize model performance. 

 
 

Responsibilities: 
  • Utilize Automatic Prompt Generation (APG) tools to create baseline prompts for complex parent-child template clusters. 

  • Run and supervise Automated Prompt Optimization (APO) tool, review the outputs, and flag when the APO reaches deadlocks or plateaus.   

  • Manually draft, test, and refine prompts to navigate complex template architectures, overcome anti-patterns, and handle edge cases where tooling is lacking or broken. Solve edge-case scenarios by designing and refining manual prompts. 

  • Monitor shadowbot runs to ensure sufficient disagreements (between human and LLM ratings) are registered, generated, and tracked.   

  • Run prompt versions against established gold data to continuously measure autorater quality against the human crowd baseline, calculating accuracy metrics such as F1 scores, precision, and recall.   

  • Draft technical launch readiness justifications (Launch Certification Documentation) for final. 


Requirement: 
  • Language Skills: Native fluency in Japanese and fluent in English. 

  • Location: Must be based in Japan.

  • Education: Bachelor’s, Master’s, or Doctorate degree in Computer Science, Data Science, Computational Linguistics, Human-Computer Interaction (HCI), Cognitive Science, or a related analytical field.  

  • Prompt Engineering & AI Expertise: At least 4 years' experience as Prompt Engineer. Proven experience tuning Large Language Models (LLMs) for strict, structured outputs, complex classification tasks, and familiarity with chain-of-thought and few-shot learning. 

  • Data Analysis: Strong proficiency in identifying error patterns, analyzing model performance, and using SQL or other data analytics tools.  

  • Technical Agility: Ability to quickly learn and master proprietary tools with minimal supervision. 

  • Communication: Excellent verbal and written communication skills. 


Optional / Preferred Skills:  
  • Familiarity with enterprise-grade LLM interfaces like the Goose API.  

  • Experience in AI model evaluation, data science, computational linguistics, or software engineering. 

  • Hands-on experience with Automated Prompt Optimization (APO) systems or tuning workflows. 

  • Linguistic expertise, including an understanding of semantics and logic.  

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MR

Marcus Rivera

Chief Revenue Officer

m.rivera@company.com
linkedin.com/in/marcusrivera
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