Principal Machine Learning Engineer

Principal Machine Learning Engineer Location: Remote Type: Contract-to-Hire Experience: 6-12+ years Education: Master's or PhD preferred LLM/Generative AI, Multi-Agent AI (Planner/Executor, ReAct, Tool-Use), RAG, Embeddings, Retrieval Optimization, NLP, Transformers, Deep Learning, Model Fine-Tuning, PyTorch, Hugging Face, LangChain/LlamaIndex, Kubernetes, Vector Databases, ML Monitoring & Observability. Core Stack: Python, PyTorch, Hugging Face, LangChain/LlamaIndex, RAG, LLMs, Transformers, Vector Databases, Kubernetes, Multi-Agent AI, ML Observability. Job Summary We are seeking 2 Principal Machine Learning Engineers to join a collaborative team building and deploying advanced AI and LLM-based solutions. The ideal candidate will have strong hands-on experience in Machine Learning, Generative AI, LLMs, RAG and multi-agent systems , with the ability to translate complex technical concepts into practical business solutions. The role requires someone who has spent the last 2-3 years heavily focused on modern AI/LLM technologies and has experience taking ML systems from development through production. Required Skills 6-12+ years of experience in Data Science and Machine Learning Engineering Strong hands-on experience building and deploying LLM-based systems Expertise in Generative AI and NLP Proven experience with multi-agent architectures , including Planner/Executor, Tool-Use Agents and ReAct-style agents Strong experience with Retrieval-Augmented Generation (RAG) Hands-on experience with embeddings and retrieval optimization Experience developing LLM/ML model evaluation frameworks Strong knowledge of Transformers and Deep Learning Experience with model fine-tuning Hands-on experience with PyTorch and Hugging Face Experience with LangChain and/or LlamaIndex Experience working with Kubernetes Experience with vector databases Experience designing and operating production-grade ML systems Experience with ML monitoring, observability and evaluation Preferred Qualifications Master's or PhD in Computer Science, Machine Learning, Artificial Intelligence, Data Science or a related field Experience architecting enterprise-scale AI/LLM platforms Experience with production agentic AI systems Strong understanding of LLM evaluation, hallucination reduction and retrieval quality Experience with cloud-based ML/AI infrastructure Strong communication and stakeholder management skills Key Responsibilities Design, develop and deploy production-grade LLM and Generative AI solutions Build and optimize RAG pipelines , embeddings and retrieval systems Design and implement multi-agent architectures Fine-tune and evaluate transformer-based models Develop scalable ML/AI services and infrastructure Build monitoring, observability and evaluation frameworks for production AI systems Collaborate with data scientists, engineers, product teams and business stakeholders Translate business requirements into scalable AI/ML solutions Provide technical leadership and mentorship across AI/ML initiatives 3B Staffing LLC