Online STEM Engineer (Remote, United States)

Online STEM Jobs in the United States (Remote, Full-Time) Rex.zone is hiring a remote, US-based STEM Engineer to build and maintain engineering systems that support AI/ML workflows such as LLM training pipelines, data labeling QA, prompt evaluation, RLHF evaluation, and dataset quality measurement. You will collaborate across NLP, computer vision, and content safety labeling to improve training data quality and model performance. What You'll Work On Design and maintain data workflows for NLP and computer vision annotation (e.g., NER, multimodal, content safety labeling) Build internal tools and dashboards for audit trails, sampling plans, and quality metrics (e.g., disagreement analysis) Standardize prompt evaluation rubrics and implement evaluator tooling Enable scalable RLHF data collection, evaluation, and feedback loops Responsibilities Own end-to-end delivery for systems supporting LLM training pipelines Build ETL/ELT jobs, data validation checks, dataset versioning, and automated tests Implement QA evaluation workflows (gold sets, consensus methods, review queues) Develop guideline compliance checks and content policy enforcement utilities Integrate labeling throughput, quality, and cost signals with partners and vendors Required Qualifications Mid-Senior experience in software engineering or data engineering with production systems Strong Python and SQL; experience building reliable pipelines and tests Familiarity with ML workflows, dataset curation, and evaluation concepts Ability to define measurable quality metrics and operational tooling Strong written communication and ability to work asynchronously (remote) Preferred Qualifications Experience with data labeling programs, annotation platforms, or vendor integrations Exposure to LLM evaluation, prompt evaluation, and rubric-based scoring Understanding of RLHF concepts and sampling strategies Familiarity with computer vision annotation formats and quality controls Background in content safety labeling, policy enforcement, or trust & safety How To Apply Apply through Rex.zone with a resume highlighting production pipeline ownership and any experience with LLM training data, QA evaluation, RLHF evaluation, NLP, computer vision annotation, or content safety labeling.