Senior Prompt Engineer: Elevate LLM Performance

Welo Global; United States; Remote; USD 57,000 - 95,000; Full time

Job summary

Welo Global is seeking a Prompt Engineer to own the end-to-end technical migration workflow for transitioning templates to LLM autoraters. You will use internal tools to maximize model performance and ensure high-quality prompts for complex template architectures.

Based in Japan, you will draft, test and refine prompts, monitor tooling outputs, and document launch readiness. Strong collaboration and analytical skills are required to succeed in this role.

Qualifications

• 4+ years as a Prompt Engineer with LLMS tuning for structured outputs.
• Proficiency in SQL or data analytics and model performance analysis.
• Excellent verbal and written communication skills.
• Native Japanese, fluent English; based in Japan.

Responsibilities

• Create baseline prompts with Automatic Prompt Generation (APG) for complex templates.
• Run and supervise Automated Prompt Optimization (APO) tools and review outputs.
• Manually draft, test and refine prompts for complex templates and edge cases.
• Monitor shadowbot runs, register disagreements, and track results.
• Compare prompts against gold data and measure accuracy (F1, precision, recall).
• Draft Launch Certification Documentation for final release.

Skills

Prompt engineering

SQL / data analytics

Communication skills

Bilingual: Japanese / English

Education

CS / DS / CL / HCI degree

Tools

Goose API

APG tooling

APO systems

Job description

Welo Global is seeking a Prompt Engineer to own the end-to-end technical migration workflow for transitioning templates to LLM autoraters. You will use internal tools to maximize model performance and ensure high-quality prompts for complex template architectures.

Based in Japan, you will draft, test and refine prompts, monitor tooling outputs, and document launch readiness. Strong collaboration and analytical skills are required to succeed in this role.