AI Data Evaluation Specialist, Large Language Models

Workster is partnering with a leading global customer experience company to recruit English-speaking AI Data Evaluation Specialists for an innovative artificial intelligence project based in Lisbon, Portugal.

If you’re passionate about AI, language technology, and data quality, this is a unique opportunity to contribute to the development of next-generation Large Language Models (LLMs). You’ll work with cutting-edge AI systems by reviewing, evaluating, and improving AI-generated responses, helping create safer, more accurate, and more reliable conversational experiences for millions of users worldwide.

Your Role

• Review and evaluate AI-generated responses using detailed annotation and quality guidelines

• Label and annotate language model outputs with accuracy and consistency

• Assess AI-generated content for quality, relevance, factual accuracy, safety, and policy compliance

• Apply complex annotation guidelines across a wide variety of scenarios and content types

• Identify inconsistencies, edge cases, and potential model issues, escalating when appropriate

• Analyze structured text, datasets, and AI-generated content to support model improvement

• Deliver high-quality work while consistently meeting productivity, quality, and accuracy targets

• Maintain strict confidentiality and comply with all project standards, security requirements, and internal procedures

• Contribute directly to the ongoing training and improvement of advanced AI systems through detailed evaluations and feedback

• 24/7 rotating schedule (Monday to Sunday) with 2 rotational days off

Your Qualifications

• Native-level fluency in English

• Good command of English (B2 level or above)

• Strong understanding of Generative AI, Large Language Models (LLMs), and AI evaluation methodologies

• Previous experience in AI data annotation, LLM evaluation, Reinforcement Learning from Human Feedback (RLHF), Supervised Fine-Tuning (SFT), Quality Assurance, Content Labeling, Trust & Safety, or similar analytical roles is highly desirable

• Excellent analytical thinking and attention to detail

• Ability to interpret and consistently apply complex written guidelines and policies

• Strong reading comprehension and written communication skills

• Comfortable working with structured text, datasets, and AI-generated content

• Ability to work efficiently in a fast-paced, quality-driven environment while meeting performance targets

• Professional, objective, and capable of handling confidential information with discretion

The Offer

• Office-based position in Lisbon, Portugal

• Comprehensive onboarding and specialized training in AI evaluation processes

• Opportunity to work on one of the world’s most advanced artificial intelligence projects

• International and multicultural working environment

• Career development opportunities within the rapidly growing AI industry

• Private health insurance

• Meal allowance

• Ongoing learning and professional development

• Modern office facilities with a collaborative team culture

• Unique opportunity to shape the future of generative AI and language technologies