AI Training Specialist (Brazil, Remote)

About the role

Rex.zone connects Brazil-aligned talent with remote, full-time AI training work supporting LLM and computer vision model improvement through high-quality data and evaluation signals.

Responsibilities

• Create and apply annotation taxonomies and guidelines
• Label text and image data; perform named entity recognition and document classification
• Conduct RLHF comparisons and preference ranking
• Execute prompt evaluation and rubric-based scoring
• Complete QA evaluation, adjudication, and error analysis
• Validate training data quality via sampling and audits
• Track inter-annotator agreement, defect rates, and calibration outcomes
• Document decisions to support consistent evaluation and dataset versioning

Requirements

• Mid-senior capability in structured evaluation and operational rigor
• Experience with data labeling or QA evaluation in production settings
• Comfort with ambiguity resolution and rubric adherence
• Strong written communication for guideline interpretation
• Familiarity with LLM evaluation concepts (helpfulness, factuality, toxicity, instruction following)

Domains You May Support

• NLP/LLM evaluation
• content safety labeling
• multilingual Portuguese/English tasks
• computer vision annotation (e.g., bounding boxes/segmentation)

Compensation

Hourly range: $30–$50/hr (USD).

Quality is measured by audit accuracy, guidelines compliance, inter-annotator agreement, defect rates, and turnaround time.