Senior Machine Learning Engineer

Details

Reddit is hiring a Machine Learning Engineer to build end-to-end production machine learning systems across its Consumer and Ads organizations. The role focuses on large-scale applied machine learning problems involving discovery, relevance, monetization, recommendations, search, advertising, and user and content understanding.

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.

Potential areas include personalized recommendations, search and ranking, advertising systems, bidding, measurement, optimization, representation learning, content understanding, model serving, 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, regression, transformers, convolutional neural networks, and graph neural networks.
• 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 qualifications include experience with recommender systems, search and ranking systems, advertising or auction systems, large-scale representation learning, multimodal embedding systems, distributed systems, real-time low-latency environments, feature engineering, model optimization, and production monitoring. Familiarity with Spark, Kafka, Ray, Airflow, BigQuery, or Redis is also valued. Experience with LLM and generative AI techniques, including evaluation, alignment, fine-tuning, knowledge distillation, RAG, agentic systems, and productionizing LLM-powered products is preferred. An advanced degree in Computer Science, Machine Learning, or a related quantitative field is also preferred.

Benefits

• Comprehensive healthcare benefits and income replacement programs.
• 401(k) with employer match.
• Global benefit programs supporting workspace, professional development, caregiving, and lifestyle needs.
• 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.

Reddit is an equal opportunity employer committed to providing reasonable accommodations for qualified individuals with disabilities and disabled veterans.