Senior Staff Machine Learning Engineer, Ads Ranking

Reddit

1d • Remote

About The Position

Reddit is a community of communities. It’s built on shared interests, passion, and trust, and is home to the most open and authentic conversations on the internet. Every day, Reddit users submit, vote, and comment on the topics they care most about. With 100,000+ active communities and approximately 116 million daily active unique visitors, Reddit is one of the internet’s largest sources of information. For more information, visit www.redditinc.com. We’re evolving and continuing our mission to bring community, belonging, and empowerment to everyone in the world. Providing a delightful and relevant experience to our users applies to our Ads like all of our offerings, and we’re excited to build a product that is best-in-class for our users and advertisers. The year ahead is a busy one - join us! We’re looking for a Senior Staff Machine Learning Engineer to join Reddit’s Ads Ranking Org. This role is part of a broader effort to enhance Reddit’s ML-powered ad ranking systems through improved model architectures, contextual embeddings, and conversion-optimized modeling.

Requirements

• 9+ years industry experience in ML Engineering / Applied ML.
• Demonstrated impact: leading cross-team technical initiatives and influencing technical direction.
• Strong fundamentals in ML systems end-to-end.
• Excellent communication: can explain tradeoffs clearly to both technical and non-technical stakeholders.
• Proven track record shipping DNN-based ranking/recs/ML models to production with measurable impact.
• Strong understanding of loss/labeling, sampling, calibration, bias/variance, train/serve skew, and online experimentation.
• Comfortable mentoring other engineers and raising modeling quality through reviews and technical guidance.

Responsibilities

• Design and train advanced ML models (e.g., DNNs, transformers) to power Reddit Ads Ranking models.
• Develop and optimize features including embeddings, contextual signals, and cross-session behavior.
• Own experimentation strategy: offline metrics, A/B design, readouts, and “next iteration” planning.
• Work closely with product, infra, and data teams to drive end-to-end model deployment and performance analysis.
• Mentor other MLEs and contribute to modeling best practices across the org.
• Shape the long-term modeling vision across one or more domains (conversion, app ads, shopping, brand, etc.).

Benefits

• Comprehensive Healthcare Benefits and Income Replacement Programs
• 401k with Employer Match
• Global Benefit programs that fit your lifestyle, from workspace to professional development to caregiving support
• Family Planning Support
• Gender-Affirming Care
• Mental Health & Coaching Benefits
• Flexible Vacation & Paid Volunteer Time Off
• Generous Paid Parental Leave

What This Job Offers

• Job Type: Full-time
• Career Level: Mid Level
• Education Level: No Education Listed
• Number of Employees: 1,001-5,000 employees