Enterprise AI Research Engineer LLMs RAG & Agents

Fabrion; San Francisco (CA); On-site; USD 180,000 - 260,000; Full time

Benefits offered by this job

Equity

Job summary

Fabrion is building the next generation of enterprise AI infrastructure in the San Francisco Bay Area. We seek an ML/AI Research Engineer to lead design, training, evaluation, and optimization of agent-native AI models that sit atop our enterprise data fabric.

You will work at the intersection of LLMs, vector search, graph reasoning, and reinforcement learning, driving end-to-end ML from data curation to deployment with cost-awareness and alignment in scope.

Qualifications

• Deep experience fine-tuning open-source LLMs using HuggingFace Transformers, DeepSpeed, vLLM, FSDP, LoRA/QLoRA.
• Worked with base and instruction-tuned models; familiar with SFT, RLHF, DPO pipelines.
• Experience building enterprise-grade RAG pipelines integrated with real-time or contextual data.

Responsibilities

• Fine-tune and evaluate open-source LLMs for enterprise use cases with structured and unstructured data.
• Build and optimize RAG pipelines using LangChain, LangGraph, LlamaIndex or Dust; integrate with vector DBs and internal knowledge graph.
• Train agent architectures (ReAct, AutoGPT, BabyAGI, OpenAgents) using enterprise task data.
• Develop embedding-based memory and retrieval chains with token-efficient chunking strategies.
• Create reinforcement learning pipelines to optimize agent behaviors (RLHF, DPO, PPO).
• Establish scalable evaluation harnesses for LLM and agent performance, including synthetic evals and explainability tools.
• Contribute to model observability, drift detection, error classification, and alignment.
• Optimize inference latency and GPU resource utilization across cloud and on-prem environments.

Skills

LLM training & inference

Agent orchestration

RAG pipelines design

Memory & retrieval

Reinforcement learning

Model evaluation & interpretability

Explainability & safety

Tools

LangChain

LangGraph

LlamaIndex

Weaviate/FAISS

Pinecone

DeepSpeed

vLLM

Job description

Fabrion is building the next generation of enterprise AI infrastructure in the San Francisco Bay Area. We seek an ML/AI Research Engineer to lead design, training, evaluation, and optimization of agent-native AI models that sit atop our enterprise data fabric.

You will work at the intersection of LLMs, vector search, graph reasoning, and reinforcement learning, driving end-to-end ML from data curation to deployment with cost-awareness and alignment in scope.