Staff Machine Learning Engineer, Retrieval

Reddit is seeking a Staff Machine Learning Engineer to provide technical leadership for the Retrieval ML team. The Ads Retrieval ML team builds machine learning systems that identify relevant advertising candidates for Reddit users.

Responsibilities:

• Define the technical direction and multi-year roadmap for ads retrieval modeling
• Design, develop, and launch candidate-generation and retrieval models for campaigns and ads
• Apply modern approaches such as two-tower architectures, representation learning, and deep learning techniques
• Improve the retrieval stack across key modeling decisions
• Work with approximate nearest-neighbor and vector retrieval systems
• Establish strong evaluation practices
• Lead offline analysis and online experiments
• Partner with downstream ranking, ads platform, auction, measurement, and product teams
• Write design documents, review code and model changes, and mentor ML engineers

Required Qualifications:

• 7+ years of industry experience in applied ML
• Deep experience with information retrieval, candidate generation, and recommender systems
• Strong understanding of retrieval modeling concepts
• Experience training, evaluating, and deploying deep learning models
• Demonstrated ownership of ML projects
• Strong command of experimental design and model evaluation
• Experience working with large-scale behavioral, contextual, or content datasets
• Strong software engineering fundamentals
• Technical leadership experience
• Excellent written and verbal communication

Preferred Qualifications:

• Experience with ads retrieval, ad serving, recommendation, search relevance, or marketplace optimization
• Experience modeling user, content, campaign, or ad interactions with sequential, graph, or multimodal signals
• Experience connecting retrieval improvements to downstream ranking, auction, conversion, revenue, or user-experience outcomes

Benefits:

• 100% remote opportunity
• Comprehensive Healthcare Benefits and Income Replacement Programs
• 401k with Employer Match
• Global Benefit programs
• Family Planning Support
• Gender-Affirming Care
• Mental Health & Coaching Benefits
• Flexible Vacation & Paid Volunteer Time Off
• Generous Paid Parental Leave