Staff ML Engineer: AI Systems Architect for FinTech

BILL; United States; On-site; USD 180,000 - 240,000; Full time

Job summary

BILL is seeking a Staff ML Engineer to raise the technical bar across its AI/ML organization. You will architect and build the next generation of ML systems spanning LLM-based extraction, fine-tuned open-weight models, intelligent routing, and data foundations.

This senior IC role influences the entire org; you will mentor engineers, set evaluation standards, and shape deployment approaches while staying hands-on with model training and production code.

Qualifications

• 8+ years in software/ML with Staff level or equivalent scope.
• Experience fine-tuning LLMs and production deployment at scale.
• Proven ability to lead technically while remaining hands-on.
• Strong background in evaluation, experimentation, and design-to-production.
• Experience with document processing and privacy-preserving ML is a plus.

Responsibilities

• Own technical direction for high‑impact ML initiatives end to end.
• Prototype, fine‑tune, and ship models; write production code.
• Lead LLM strategy; evaluate build‑vs‑buy across models.
• Translate literature into rigorous experiments and ablations.
• Design data flywheel: labeling, human‑in‑the‑loop, drift monitoring.
• Set engineering standards for evaluation, reproducibility, deployment.
• Mentor engineers; influence roadmaps with product and platform teams.

Skills

Staff-level leadership

Hands-on ML engineering

PyTorch

Distributed training

Experimentation & AB testing

Model fine-tuning (LoRA/QLoRA)

Production ML systems

Data reasoning

Education

Bachelor's degree or higher

Tools

PyTorch

LoRA/QLoRA

Hugging Face Transformers

Vector stores

Model serving infra (production)

Job description

BILL is seeking a Staff ML Engineer to raise the technical bar across its AI/ML organization. You will architect and build the next generation of ML systems spanning LLM-based extraction, fine-tuned open-weight models, intelligent routing, and data foundations.

This senior IC role influences the entire org; you will mentor engineers, set evaluation standards, and shape deployment approaches while staying hands-on with model training and production code.