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 OnText labeling for NLP tasks (classification, NER, summarization) and rubric-based decision makingPrompt evaluation and LLM response scoring (helpfulness/harmlessness/honesty)RLHF-style preference ranking and pairwise judgmentsQA evaluation using checklists, sampling plans, spot checks, and gold tasksComputer vision annotation support (bounding boxes, polygons, keypoints) as neededContent safety labeling to ensure policy-compliant outputsDocument edge cases, track error patterns, and propose guideline/rubric improvementsAsynchronous collaboration with data ops, QA,



and project leads in a remote workflowRequired QualificationsMid-Senior experience in data labeling or data annotation operationsStrong attention to detail and ability to follow structured rubrics and guidelinesFamiliarity with NLP concepts (classification, NER, sentiment) and LLM training pipelinesAbility to explain labeling decisions clearly and maintain consistent quality under deadlinesPreferredExperience with RLHF, large language model evaluation, and audit-ready QA workflowsExposure to computer vision annotation formats and inter-annotator agreement methodsBackground supporting AI labs, tech startups, BPOs, or annotation vendorsEmployment DetailsWorkplace: Remote (asynchronous collaboration). Employment Type: FULL_TIME. This role aligns to Madrid job-search intent for remote opportunities while operating fully online.

📌 Remote Data Labeling Jobs In Madrid
🏢 Rex.zone
📍 Madrid