Senior Data Annotator Jobs in Denver at Rex.zone

About Rex.zone

Rex.zone connects skilled annotators with AI labs, tech startups, BPOs, and annotation vendors to help build LLM training pipelines at scale. This is a remote, full-time role available to candidates in the US, including Denver, with schedules handled online through Rex.zone.

About The Role

As a Senior Data Annotator, you will label and evaluate multimodal training data used in AI/ML products. You will deliver strong training data quality by following rubrics, documenting edge cases, and supporting model performance improvement through consistent, policy-aware decisions.

What You Will Do

• Produce and review high-quality data labeling and data annotation outputs across text, image, and conversational datasets
• Perform RLHF ranking / preference labeling for large language model evaluation
• Execute prompt evaluation and response grading using project rubrics
• Apply named entity recognition (NER) and span labeling with clear boundary rules
• Complete computer vision annotation tasks (bounding boxes, polygons, keypoints) as needed
• Run QA evaluation, error categorization, and spot checks to improve training data quality
• Escalate ambiguous cases, write edge-case notes, and propose rubric clarifications
• Join calibration sessions to maintain inter-annotator agreement

Required Qualifications

• Prior experience in data annotation or data labeling for AI/ML systems
• Strong attention to detail and consistent annotation guidelines compliance
• Comfort with NLP tasks and rubric-based evaluations
• Ability to document decisions clearly and communicate edge cases
• Availability for full-time remote work aligned to project schedules

Preferred Qualifications

• Experience with large language model evaluation and LLM training pipelines
• Experience with content safety labeling or safety taxonomies
• Mentoring/quality champion experience or leading calibration

Compensation

$30–$50/hr (USD).

Remote (US-based).