Founding Machine Learning Engineer

About the Role

This is a founding-level, hands-on ML engineering role at a fast-growing Series A AI startup in the Bay Area, specializing in high-quality training data, post-training data pipelines, and model evaluation for frontier AI labs and enterprises. You'll work closely with leadership to design, train, and ship production-grade ML systems — while helping shape the technical culture and infrastructure from the ground up.

This role is fully on-site in Mountain View, CA. Candidates must be authorized to work in the US without visa sponsorship.

What You'll Do

• Build and optimize end-to-end ML pipelines, from data ingestion through to production deployment.
• Implement and fine-tune LLMs, embeddings, and generative models for real-world applications.
• Develop efficient training and inference systems leveraging distributed compute at scale.
• Partner with data and product teams to translate ideas into measurable ML impact.
• Contribute to model monitoring, evaluation, and continual learning frameworks.
• Establish best practices in model versioning, reproducibility, and scalability across the organization.

What We're Looking For

Required

• 3–10 years of hands-on experience as an ML Engineer, Applied Scientist, or Research Engineer.
• Proficiency in Python and at least one of PyTorch, TensorFlow, or JAX.
• Proven experience building production-grade, end-to-end ML pipelines (data ingestion, training, deployment).
• Experience implementing and fine-tuning LLMs, embeddings, and generative models for real-world use cases.
• Hands-on experience with distributed training/inference and scalable ML systems.
• Familiarity with cloud platforms (AWS, GCP, or Azure) and ML tooling such as MLflow or Weights & Biases.
• Strong collaboration skills with cross-functional data and product teams.
• Bias for action, ability to work autonomously, and eagerness to build from scratch.

Nice to Have

• Experience with RL environments or evaluation frameworks for AI models.
• Background in agentic systems, tool-use pipelines, or multi-step execution trajectories.
• Prior experience at an early-stage startup or in a founding-engineer capacity.

Compensation & Benefits

• Salary: $220,000 – $300,000 per year, depending on experience.
• Equity participation as a founding team member.
• Opportunity to directly shape technical direction, culture, and hiring at an early-stage, high-growth company.

Location

• On-site in Mountain View, California.
• No visa sponsorship available — candidates must have existing US work authorization.