Jobs in Pasadena, CA

About the role

As a Staff Machine Learning Engineer, you’ll own AI-driven products end to end, from the prototype that proves an idea works to the production system the mission depends on. You work fluently across the modern stack: large language models, agentic systems, retrieval, embeddings, fine-tuned models, and the evaluation harnesses that catch them when they drift.

What you'll bring

• 6+ years building production backend software, with a track record of shipping and operating ML-driven functionality.
• Mastery of data structures and algorithms, and the judgment to translate user needs into practical solutions.
• Hands-on depth with LLMs and agentic systems (prompt and context engineering, tool use, retrieval and RAG) and the broader ML toolkit such as PyTorch, plus experience defining evals to measure and improve quality.
• Fluency authoring production APIs in Python.
• High agency and a bias to action in ambiguous, fast-moving problems, plus the curiosity, generosity, and love of teaching that lifts a whole team.
• Experience with knowledge graphs, information retrieval at scale, or LLM fine-tuning and post-training.
• A pull toward high-stakes, real-world problems where the work actually ships and someone depends on the answer.
• Primer works closely with the U.S. defense and intelligence establishment.
• Any offer of employment is conditioned on an applicant or employee being able to meet any applicable government contract requirements.
• The company may rescind any offer of employment to an applicant or terminate an employee if the applicant or employee is unable to perform the functions of the position in compliance with applicable government contracts or if an applicant or employee makes a false attestation of compliance.
• Rust a plus

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