Rex.zone
Senior Data Annotator Jobs in London
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Senior Data Annotator (Remote, Full-time)
Join Rex.zone to produce high-quality training data for AI/ML systems. You will lead annotation workstreams for LLM training pipelines, generating gold-standard labels, RLHF preference data, and QA evaluation outputs to improve downstream model performance across NLP, computer vision, and content safety workflows.
What You Will Do
- Execute and review data annotation tasks across text, image, and multimodal datasets
- Create and refine labeling taxonomies, edge-case definitions, and decision rubrics
- Perform RLHF preference ranking, pairwise comparisons, and rubric-based scoring
- Run QA evaluation, error analysis, and inter-annotator agreement checks
- Complete prompt evaluation for instruction-following, helpfulness, and harmlessness
- Label and validate named entity recognition datasets and entity linking rules
- Contribute to content safety labeling (toxicity, self-harm, hate, policy compliance)
- Maintain annotation guidelines compliance documentation and change logs
- Collaborate with engineering and data operations to improve tooling and throughput
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Requirements
- Mid-senior experience in data annotation, data labeling, or AI/ML evaluation
- Experience with RLHF workflows and rubric-based evaluation
- Strong writing and reasoning skills for LLM evaluation and prompt evaluation
- Comfort with QA evaluation methods (sampling, audits, consistency checks)
- Familiarity with structured schemas such as named entity recognition
- Ability to work independently in a remote environment with high attention to detail
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Success Metrics
- Improved training data quality (audit pass rates, lower defect rates)
- High agreement and stable calibration across annotators/reviewers
- Clear documentation of edge cases, rubric updates, and QA outcomes
Pay
$30–$50 per hour (base pay; rate depends on skills and experience).
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