Staff Machine Learning Engineer, Homefeed

Pinterest • San Francisco, CA

6d • $189,308 - $389,753 • Remote

About The Position

Pinterest’s Retrieval team builds shared machine learning capabilities to connect people with relevant ideas. This Staff Machine Learning Engineer will advance those capabilities through agentic AI, primarily by owning a major technical area of Reflex, Pinterest’s effort to automate and accelerate recommendation research and development. The role involves building agents that investigate opportunities, implement changes, run experiments, and learn from their results, while working with technical leaders and remaining hands-on with complex engineering and modeling problems.

The position also contributes to generative retrieval, particularly Semantic IDs: structured representations of content that recommendation models can generate and use to retrieve relevant items. The work combines applied AI research, production engineering, and technical leadership, improving recommendation models as well as the way engineers build them. The role is an individual contributor position; prior people management is not required.

The role may be situated anywhere in the country, with in-office collaboration required 1–2 times per quarter. The position is not eligible for relocation assistance. US-based applicants only. The base salary range is $189,308–$389,753 USD, and the position is also eligible for equity.

Requirements

• Bachelor’s degree in Computer Science, Machine Learning, or a related field, or equivalent practical experience.
• At least 8 years of experience building and shipping ML or AI systems, including substantial hands-on engineering and technical leadership.
• Demonstrated experience building LLM agents or other agentic AI systems for complex tasks, with a clear approach to evaluating and improving their performance.
• Strong ML fundamentals and depth in one or more relevant areas, such as applied LLMs, representation learning, recommendation systems, retrieval, or ML systems.
• Experience taking research ideas into reliable production systems and evaluating their impact through meaningful experiments.
• Strong software engineering skills, including designing maintainable systems, implementing difficult components, and conducting thorough technical reviews.
• Experience leading a substantial technical area, making decisions under ambiguity, and collaborating effectively across teams.
• Track record of mentoring engineers and raising the quality of a team’s technical work.
• Clear written and verbal communication, including the ability to explain technical tradeoffs to different audiences.
• Disciplined use of AI in one’s own work, including verification of generated code, analysis, and conclusions.

Responsibilities

• Own and advance a major technical area in automated recommendation research within Reflex, collaborating with technical leads and partner teams.
• Build LLM agents that connect hypothesis generation, implementation, experiment execution, evaluation, and learning from previous results.
• Develop rigorous evaluations for agent behavior and research outputs, and use them to improve quality, reliability, and efficiency.
• Contribute to generative retrieval models, particularly Semantic ID learning, evaluation, and integration into production recommendation systems.
• Take promising ideas from research and prototypes through offline evaluation, online experimentation, and production launches.
• Build reliable integrations with ML development infrastructure and make tradeoffs across model quality, iteration speed, compute cost, and operational complexity.
• Raise technical quality through hands-on implementation, design and code reviews, documentation, and mentorship.
• Work with research, recommendation, and ML infrastructure teams to shape technical approaches, resolve dependencies, and support adoption.
• Identify and apply relevant advances from research, and contribute new methods where existing approaches fall short.

What This Job Offers

• Job Type: Full-time
• Career Level: Senior