Senior Machine Learning Engineer, Ads

Details

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 101M+ daily active unique visitors, Reddit is one of the internet’s largest sources of information. For more information, visit redditinc.com.

Reddit has a flexible workforce. If you live close to one of our physical office locations our doors are open for you to come into the office as often as you'd like. If you don't live near one of our offices, you can apply to work remotely in any country in which we have a physical presence.

Team Description

Reddit is hiring across multiple Ads teams including Ads Prediction, App Ads & Conversion Modeling, Ads Measurement Modeling, Ads Targeting & Retrieval, Advertiser Optimization, and Ads Marketplace. Brief descriptions of the teams follow:

• Ads ML Serving Team: Builds a reliable, scalable, and efficient ML serving stack. Focus on long-term architecture, tight integration with the ads serving stack, CPU/GPU performance optimization, and model velocity tools like observability libraries and quality gating.
• Attribution & Identity Team: Builds attribution systems and identity solutions for measuring campaign impact and creates experimentation tools and platforms that improve usability, transparency, and performance insights.
• Ads Measurement Modeling Team: Horizontal ML team focused on proving Reddit Ads value while maintaining privacy compliance (Modeled Identity, Modeled Conversions, ATT opt-out utilities).
• Ads Targeting and Retrieval Team: Designs and implements large-scale ML systems for targeting products and retrieval systems for contextual and behavioral targeting.
• Advertiser Optimization Team: Two horizontal teams focused on advertiser outcomes — Recommendations & Forecasting (ML-driven tools) and Bidding/Pacing (algorithms like TCPA, TROAS) to drive marketplace dynamics.
• Ads Marketplace Quality Team: Optimizes auction and pricing efficiency, supply optimization, and ad relevance.
• App Ads and Conversion Modeling Teams: Focus on app install models and deep neural networks for iOS/Android conversions and RoAS optimization.
• Ads Prediction Team: Drives innovation across signals, features, model architecture, and infrastructure, including Core Ads Ranking and Engagement Modeling.

Reddit Ads offers opportunities to work on large-scale systems that directly impact advertisers, users, and revenue.

Role Description

Join the Ads team as a Machine Learning Engineer and become a key contributor to Reddit’s business. This hands-on role covers the full ML system lifecycle: research and modeling, deployment, and optimization in production. Your work will impact ad ranking, bidding, measurement, and optimization.

Responsibilities

• Design, build, and deploy industrial-level machine learning models for ad ranking, bidding, and optimization.
• Own the ML lifecycle from ideation and research to production serving and maintenance.
• Perform systematic feature engineering to convert raw, diverse data into high-quality features that drive model performance.
• Collaborate with product managers, data scientists, and engineers to translate business challenges into ML solutions.
• Improve reliability and stability of ML systems by building monitoring, alerting, and automated retraining pipelines.
• Research new algorithms, stay current with state-of-the-art ML techniques, and contribute to team strategy and roadmap.

Requirements

• At least 3+ years of end-to-end experience training, evaluating, and deploying ML models in production.
• Proficient in one or more general-purpose programming languages (e.g., Python, Scala) with solid software development best practices.
• Hands-on experience with a major ML framework (e.g., TensorFlow, PyTorch) and deep understanding of core ML concepts and algorithms.
• Proven ability to work effectively with cross-functional teams (product managers, data scientists) to translate business needs into technical solutions.
• Track record of using ML to drive KPI improvements and solve complex, real-world problems.

Bonus Points

• Experience working in the Ads domain.
• Experience or interest in the advertising business and understanding customer needs.
• Advanced degree (MS/PhD) in a quantitative field.
• Familiarity with distributed systems and large-scale data processing technologies (e.g., Spark, Kafka).

Pay Transparency & Benefits

• Base pay range (US): $216,700 - $303,400 USD per year.
• In addition to base salary, eligible for equity (RSUs) and potentially commission depending on position.
• Benefits for U.S.-based employees include medical, dental, and vision insurance, 401(k) with employer match, generous vacation time, and parental leave. See https://www.redditinc.com/careers/ for more details.

Interview & Privacy Notes

• In select roles and locations, interviews may be recorded, transcribed, and summarized by AI; candidates can opt out prior to interviews.
• During interviews, Reddit collects Identifiers, Professional and Employment-Related Information, Sensory Information (audio/video), and any other information you choose to share; recordings are deleted promptly after hiring decisions.

Equity, Inclusion & Accommodations

• Reddit is an equal opportunity employer and is committed to building a diverse workforce. Reasonable accommodations are available for applicants with disabilities during the application and interview process.