Founding Engineer ($150,000 - $250,000 + Equity) at Series A AI infrastructure startup

Jack & Jill/External ATS • San Francisco, CA

1d • $150,000 - $250,000

About The Position

Join an elite team building the foundational platform for LLM alignment and reinforcement learning. You will own the development of core infrastructure, Python SDKs, and developer workflows that enable foundation labs and enterprise teams to train and evaluate AI models at scale. This is a high-ownership role bridging full-stack systems with cutting-edge machine learning.

Requirements

• Elite Python engineer with a strong background in distributed systems, Docker, and cloud-native infrastructure.
• Product-minded builder with a deep interest in ML fundamentals, reinforcement learning, and evaluation frameworks.
• Experience designing developer-facing tools such as SDKs, CLIs, or complex API surfaces with high technical aptitude.

Responsibilities

• Design and implement backend systems for reinforcement fine-tuning (RFT) jobs and data flow primitives.
• Build and iterate on a high-quality Python SDK, focusing on ergonomics, reliability, and elite developer experience.
• Partner directly with customers at frontier labs to translate real-world feedback into scalable product abstractions.

What This Job Offers

• Job Type: Full-time
• Career Level: Mid Level
• Education Level: No Education Listed