Remote Data Labeling Jobs in Madrid (Fully Remote)

Rex.zone is hiring for a full-time, fully remote data labeling role focused on training-data creation and quality control for AI/ML systems. You will label and evaluate text, images, audio, and conversations used in large language model evaluation and computer vision annotation workflows, improving training data quality, annotation consistency, and model performance.

What You’ll Work On

Text labeling for NLP tasks (classification, NER, summarization) and rubric-based decision making

Prompt evaluation and LLM response scoring (helpfulness/harmlessness/honesty)

RLHF-style preference ranking and pairwise judgments

QA evaluation using checklists, sampling plans, spot checks, and gold tasks

Computer vision annotation support (bounding boxes, polygons, keypoints) as needed

Content safety labeling to ensure policy-compliant outputs

Document edge cases, track error patterns, and propose guideline/rubric improvements

Asynchronous collaboration with data ops, QA,



and project leads in a remote workflow

Required Qualifications

Mid-Senior experience in data labeling or data annotation operations

Strong attention to detail and ability to follow structured rubrics and guidelines

Familiarity with NLP concepts (classification, NER, sentiment) and LLM training pipelines

Ability to explain labeling decisions clearly and maintain consistent quality under deadlines

Preferred

Experience with RLHF, large language model evaluation, and audit-ready QA workflows

Exposure to computer vision annotation formats and inter-annotator agreement methods

Background supporting AI labs, tech startups, BPOs, or annotation vendors

Employment Details

Workplace: Remote (asynchronous collaboration). Employment Type: FULL_TIME. This role aligns to Madrid job-search intent for remote opportunities while operating fully online.

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📌 Remote Data Labeling Jobs in Madrid (Valencia)
🏢 Rex.zone
📍 Valencia