ML Research Engineer

We're looking for ML Engineers to join White Circle, an AI Safety company building the safety, reliability, and optimization layer for AI systems through natural-language policies it automatically tests, enforces, and improves at scale. Backed by $70M (Series A) from top funds and senior leaders at OpenAI, Anthropic, HuggingFace, Mistral, DeepMind, and others, White Circle processes 100M+ API calls monthly and fine-tunes and trains its own LLMs to run faster and cheaper than open or proprietary models. You will • Turn petabytes of unstructured text into a structured, explorable view: topics, clusters, segments, trends, anomalies. • Build scalable representation pipelines: sampling, preprocessing, embeddings at scale, indexing, and retrieval. • Use LLMs for labeling, weak supervision, data enrichment, and automated diagnostics, with cost/quality controls. • Translate findings into product and operational decisions, and ship self-serve datasets, data models, and dashboards. • Work with engineering and research to align pipelines with production constraints (latency, cost, privacy). Requirements • Strong Python and SQL, with production-grade pipeline engineering (not just notebooks). • Applied NLP/ML on real-world text: embeddings, clustering, topic modeling, semantic search, classification. • Experience at scale: distributed processing, large-scale storage and querying, performance-cost tradeoffs. • Evaluation of fuzzy problems: offline/online metrics, human-in-the-loop labeling, inter-annotator agreement, drift monitoring. • Prior work with safety/moderation datasets, policy/rule systems, or high-volume logging/observability. • Relocation to Paris or London (hybrid) required. Bonus • Public builder footprint: open-source models, datasets, or frameworks on HuggingFace/GitHub, papers, or technical posts. • Experience at a frontier or near-frontier lab, or leading open-source model releases. • RL for LLMs beyond standard RLHF: online RL, GRPO-style methods. • Moderation, safety, or classification models at scale; multilingual model training. We offer • Competitive salary + equity. • Hybrid work from central London or Paris office, relocation support for Paris after probation. • Premium private health insurance, mental health support, flexible time off. • Lunch and dinner covered in the office, L&D budget, all hardware and tools you need. • Team off-sites twice a year. Find more English Speaking Jobs in France on Arbeitnow