AI Trainer Jobs in Brazil
About The Role As an AI Trainer, you will improve large language models by producing high-quality training signals through data labeling, RLHF preference rankings, and rubric-based evaluations. You will support end-to-end LLM training pipelines with consistent, well-documented decisions that improve instruction following, reasoning quality, and content safety outcomes.
What You Will Do
- Perform data labeling for NLP tasks (intent classification, summarization checks, factuality review, named entity recognition)
- Execute RLHF work: pairwise ranking, rubric-based scoring, and short rationales
- Conduct prompt evaluation and response quality scoring using detailed rubrics
- Run QA evaluation, track error categories, and contribute to guideline updates
- Support content safety labeling for policy-sensitive topics
- Collaborate with engineering partners on edge cases, sampling strategies, and quality thresholds
Core Workstreams
- LLM evaluation (instruction following, reasoning quality, refusal behavior)
- Training data quality audits (spot checks, adjudication, gold set creation)
- Annotation operations (calibration sessions, reviewer alignment)
- Occasional multimodal evaluation or computer vision annotation when required
Qualifications
- Mid-senior experience in data operations, evaluation, QA, or applied AI workflows
- Strong written communication and ability to produce consistent decision rationales
- Attention to detail with rubric-based scoring and annotation guidelines compliance
- Familiarity with NLP concepts, LLM behavior, and training data quality practices
Employment Details Remote, full-time role with Rex.zone. Compensation: $30–$50 per hour (USD), depending on scope and assignment. How To Apply Apply on Rex.zone via the AI Trainer jobs in Brazil page. Apply tot his job Apply To this Job Apply To This Job