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Senior Prompt Engineer

Remote from Spain·Full-time·Added 2 months ago

Welo Global

10 open roles

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Overview

Job details

Full-time hours
Per the ad.
Fully remote
Only from certain places, per the ad: “Must be based in Spain.”

Requirements

Have the right to work in Spain
Welo Global doesn't mention sponsorship in the ad.
Speak fluent Spanish
Listed as a requirement in the ad.
Work in English
English is required, per the ad.
Have 4+ years of experience
Senior-level role.
University degree
“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.” — per the ad.

Requirements

What we're looking for

Language Skills: Native fluency in Spanish and fluent in English.
Location: Must be based in Spain.
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.

Nice to have

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.

The role

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.

What you'll do

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.

About Welo Global

Welo Global is a language services provider delivering enterprise localization, AI training data, multilingual content, and IP-related language solutions through a portfolio of specialized brands, including Welocalize, Park IP, Welo Life Sciences, and Welo Data. The company states it has operated for over 25 years, describes itself as 'ISO-certified. AI-enabled. Built for scale.', and reports being named a Leader in The Forrester Wave™: Localization Services, Q3 2026. Its stated use cases span enterprise localization, drug and medical device development support, intellectual property prosecution and foreign filing, international digital marketing, and AI model development and training.

For professionals in Spain, Welo Global's current openings include remote, Spain-based roles such as 'Project Lion - Senior Prompt Engineer - Spain (Remote, Part-Time)', 'Expert Rater Project - French (Spain)', and 'Expert Rater Project - German (Spain)', alongside numerous multilingual linguist, copy editing, and quality roles across other markets. The company describes a 'rigorously governed global workforce' and publishes its careers site in multiple languages, including Spanish.

Industry: Language Services
Website: weloglobal.com

Good to know if you are moving

Current openings include Spain-based remote roles, such as 'Project Lion - Senior Prompt Engineer - Spain (Remote, Part-Time)', 'Expert Rater Project - French (Spain)', and 'Expert Rater Project - German (Spain)'.
The company describes a 'rigorously governed global workforce' and markets itself as 'ISO-certified. AI-enabled. Built for scale.'
Welo Global was named a Leader in The Forrester Wave™: Localization Services, Q3 2026.
Its careers site navigation is available in multiple languages, including Spanish (Español), German, French, Italian, Chinese, and Japanese.

All open roles at Welo Global