Sr. Machine Learning Engineer, Responsible AI– Applied Research Science

The Responsible AI team is part of the Advanced Technologies Group (ATG), Pinterest’s advanced machine learning team. ATG’s goal is to keep Pinterest at the forefront of machine learning technology across multiple use cases including recommendations, ranking, content understanding, and more. It is an applied team that works horizontally across the company on state of the art AI and ML and works on directly bringing that technology to the product in collaboration with product engineering teams. The team also publishes its work in applied research conferences, but the main goal of the team is to have a direct impact on business metrics.

At Pinterest our goal is to inspire pinners (our users) to live the life they love. The product is powered by state of the art ML algorithms which are used to understand both the billions of visually rich items on the platform and the interests of our 550M+ monthly active users and recommend inspiring personalized content to them. What this means is that ML at Pinterest is not only multi-modal utilizing image, text, and graph signals as input, but it needs to operate at a very large scale and often in a real time interactive user experience.

Pinterest is known for being a positive and inspirational place on the internet and we believe that inspiration begins with representation and belonging. The Responsible AI team is a horizontal team that collaborates across the company on various initiatives. These range from Generative AI alignment, evaluation, and mitigations - ensuring these models are safe, bias-free, and aligned with Pinterest’s vision and policies - to championing ML Fairness and developing user-facing features that enhance our product for all users. This includes launching groundbreaking features such as user-controllable skin tone, hair pattern search refinements, and more recently, body type.

We are looking for a Sr Machine Learning Engineer. You’ll help shape forward-thinking projects, develop advanced ML approaches rooted in fairness and equitability, and pioneer responsible AI safeguards for emerging technologies. By joining this team, you’ll make a lasting impact on our Pinners, our business, and the evolution of ethical AI at Pinterest.

What you'll do:

• Design and drive projects in the responsible AI frontier to identify, avoid, and mitigate bias across a wide range of ML applications at Pinterest. These include but are not limited to Gen AI product evaluations, foundation models safety fine tuning and alignment, and Red Teaming. 
• Collaborate with other engineering teams (trust and safety, ML Platform, Content Understanding, Search, Homefeed,) to leverage their platforms and signals and work with them to collaborate on the adoption and evaluation of Responsible AI practices and ML Fairness tooling across Pinterest.
• Mentor junior engineers on the Responsible AI team and across the company on the R-AI space.
• Work with the team and senior leaders at the company to define and drive technical strategy in this area.

What we're looking for:

• Extensive, real-world experience applying advanced ML methods to production systems, with a strong track record in responsible technology - spanning fairness, ethics, and broader societal considerations.
• Deep familiarity with cutting-edge ML architectures (e.g., transformer-based models, 2-tower architectures, LLMs and VLMS) and their applications in large-scale Search and Recommender Systems.
• Proven ability to measure, deploy, and refine fairness interventions and broader Responsible AI solutions at scale, bridging state-of-the-art research with tangible product impact.
• 4+ years working experience in the engineering teams that build large-scale ML-driven user-facing products
• 1+ years experience leading cross-team engineering efforts.
• Masters or PhD in Comp Sci or related fields

Nice to have:

• Publications at top ML conferences
• Experience using Cursor, Copilot, Codex, or similar AI coding assistants for development, debugging, testing, and refactoring
• Familiarity with LLM-powered productivity tools for documentation search, experiment analysis, SQL/data exploration, and engineering workflow acceleration
• Expertise in scalable realtime systems that process stream data
• Passion for applied research and the Pinterest product

Relocation Statement:

• This position is not eligible for relocation assistance. Visit our PinFlex page to learn more about our working model.

In-Office Requirement Statement:

• We let the type of work you do guide the collaboration style. That means we're not always working in an office, but we continue to gather for key moments of collaboration and connection.
• This role will need to be in the office for in-person collaboration 1-2 times per quarter and therefore can be situated anywhere in the United States. 

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