Machine Learning Engineer

Details

Reddit is hiring Machine Learning Engineers across its Consumer and Ads organizations to build end-to-end machine learning systems, from research and modeling through production deployment. The role focuses on large-scale applied machine learning for discovery, relevance, advertising, and user engagement.

Responsibilities

• Design, build, and deploy production-grade machine learning models and systems at scale.
• Own the full machine learning lifecycle, including problem definition, feature engineering, training, evaluation, deployment, and monitoring.
• Build scalable data and model pipelines with strong reliability, observability, and automated retraining.
• Work with large-scale datasets to improve ranking, recommendations, search relevance, prediction, content and user understanding, and optimization systems.
• Partner with Product, Data Science, Infrastructure, and Engineering teams to translate complex problems into machine learning solutions.
• Improve system performance across latency, throughput, and model quality metrics.
• Research and apply state-of-the-art machine learning and AI techniques, including deep learning, graph-based models, transformers, and LLM evaluation and alignment.
• Contribute to technical strategy, architecture, and the long-term machine learning roadmap.
• Work on systems including personalized recommendations, search and ranking, advertising ranking and bidding, content and user representations, large-scale machine learning pipelines, model serving infrastructure, real-time decision systems, and LLM-driven experiences.

Requirements

• 3–5+ years of experience building, deploying, and operating machine learning systems in production.
• Strong programming skills in Python, Java, Go, or similar languages, with solid software engineering fundamentals.
• Strong understanding of machine learning algorithms, including XGBoost, random forests, regressions, transformers, CNNs, and GNNs.
• Hands-on experience with modern machine learning frameworks such as PyTorch or TensorFlow.
• Experience designing scalable machine learning pipelines, data processing systems, and model serving infrastructure.
• Ability to work cross-functionally and translate ambiguous product or business problems into technical solutions.
• Experience improving measurable metrics through applied machine learning.
• Preferred experience with recommender systems, search and ranking systems, advertising or auction systems, large-scale representation learning, or multimodal embedding systems.
• Familiarity with distributed systems and large-scale data processing technologies such as Spark, Kafka, Ray, Airflow, BigQuery, and Redis.
• Experience with real-time systems and low-latency production environments.
• Background in feature engineering, model optimization, and production monitoring.
• Experience with LLM and generative AI techniques, including LLM evaluation, alignment, fine-tuning, knowledge distillation, RAG, agentic systems, and productionizing LLM-powered products at scale.
• An advanced degree in Computer Science, Machine Learning, or a related quantitative field is preferred.

Potential Teams

• Ads Measurement Modeling
• Ads Targeting and Retrieval
• Advertiser Optimization
• Ads Marketplace Quality
• Ads Creative Effectiveness
• Ads Foundational Representations
• Ads Content Understanding
• Ads Ranking
• Feed Relevance
• Search and Answers Relevance
• ML Understanding
• Notifications Relevance

Benefits

• Comprehensive healthcare benefits and income replacement programs.
• 401(k) with employer match.
• Global benefit programs covering workspace, professional development, and caregiving support.
• Family planning support.
• Gender-affirming care.
• Mental health and coaching benefits.
• Flexible vacation and paid volunteer time off.
• Generous paid parental leave.
• Equity in the form of restricted stock units; select positions may also be eligible for commission.
• U.S.-based employees may receive medical, dental, and vision insurance, a 401(k) program with employer match, vacation time, and parental leave.

Additional Information

The base salary range for this position is $185,800–$260,100 USD. The posting may span more than one career level. In select roles and locations, interviews may be recorded, transcribed, and summarized by artificial intelligence, with an option to opt out before scheduled interviews. Reddit is an equal opportunity employer and provides reasonable accommodations for qualified individuals with disabilities and disabled veterans.