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.