Applied AI Research Engineer - Document Understanding

LlamaIndex Inc.; San Francisco (CA); On-site; USD 140,000 - 230,000; Full time

Job summary

LlamaIndex is hiring an AI Research Engineer to join the document understanding team in San Francisco. You will work at the intersection of applied research and engineering, prototyping quickly and turning promising approaches into production systems used by customers.

You’ll develop vision‑language models, build data pipelines, and evaluate post‑training/fine‑tuning to improve accuracy, latency, and cost. Collaborative work with engineering and customers is expected.

Qualifications

• 3–7 years of experience in machine learning engineering, applied research, or research engineering.
• Strong ML foundation, including hands‑on experience benchmarking and training models.
• Strong Python skills and comfort with modern ML tooling, especially PyTorch.
• Experience with computer vision, vision‑language models, NLP, document AI, OCR, extraction, or agentic AI systems.
• Ability to build experiments, evaluate results, and iterate quickly toward measurable performance improvements.
• Strong engineering judgment and ability to write clean, production‑quality code.
• Comfort working in a fast‑paced startup environment with high ownership and limited structure.
• Adaptable, scrappy, and self‑directed — someone who can figure things out without waiting to be told.
• Strong technical writing and communication skills.

Responsibilities

• Develop and train vision-language models for document processing and document understanding.
• Build data pipelines for data curation, synthetic data generation, labeling, and benchmark creation.
• Evaluate base models and perform post-training or fine-tuning to hit specific performance targets.
• Improve model accuracy, latency, and cost-effectiveness across real-world document workflows.
• Design and maintain benchmarks to measure extraction quality, layout understanding, OCR performance, reasoning accuracy, and end-to-end system reliability.
• Work with messy real-world documents, including PDFs, scanned documents, tables, charts, forms, and multi-page enterprise documents.
• Collaborate with engineering to move successful research prototypes into production.
• Work directly with customers when needed to translate product requirements into benchmarks, experiments, and model improvements.
• Stay close to the latest research in vision-language models, document AI, post-training, synthetic data, and agentic systems.
• Use modern AI coding workflows and tools to move quickly.

Skills

Python

PyTorch

ML engineering

Vision-language

Tools

vLLM

Pydantic

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ruff

mypy

Claude Code

Cursor

Job description

LlamaIndex is hiring an AI Research Engineer to join the document understanding team in San Francisco. You will work at the intersection of applied research and engineering, prototyping quickly and turning promising approaches into production systems used by customers.

You’ll develop vision‑language models, build data pipelines, and evaluate post‑training/fine‑tuning to improve accuracy, latency, and cost. Collaborative work with engineering and customers is expected.