Data Labeling Jobs in Brazil

Role Overview

Rex.zone is hiring for remote, full-time data labeling work supporting AI/ML training and evaluation pipelines. You will create high-quality labeled datasets and perform structured evaluations that improve model performance across real-world workflows.

What You’ll Do

• Produce accurate labels for NLP tasks (classification, summarization, intent labeling) and Named Entity Recognition (NER)
• Contribute to RLHF workflows by ranking/scoring model outputs using defined rubrics
• Perform prompt evaluation, response grading, and factuality/safety checks for LLM evaluation
• Execute QA evaluation: audits, error taxonomy tracking, and resolving label disagreements
• Follow annotation guidelines with high consistency and document edge cases to improve clarity

Requirements

• Experience in data labeling/data annotation or AI/ML evaluation workflows
• High attention to detail and strong gui...