Senior Machine Learning Engineer

Reddit

45d • $216,700 - $303,400

About The Position

Reddit is a community of communities, built on shared interests, passion, and trust. Machine learning is central to how millions of people discover, connect, and engage with human conversations on Reddit. ML engineers tackle impactful problems in large-scale applied machine learning, working on personalized recommendations, search, advertising systems, and marketplace dynamics. This role offers the opportunity to work on a wide range of high-impact problems across the Reddit ecosystem, building systems end-to-end from research and modeling to production deployment, and shaping the future of discovery, relevance, and monetization at Reddit. This role is ideal for those who love working on complex, real-world ML problems at massive scale.

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
• A strong grasp of ML fundamentals: algorithms, from classic statistical learning (XGBoost, Random Forests, regressions) to DL architectures (Transformers, CNNs, GNNs)
• Hands-on experience with modern ML frameworks (e.g., PyTorch, TensorFlow)
• Experience designing scalable ML 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

Nice To Haves

• Experience with recommender systems, search/ranking systems, advertising/auction systems, large-scale representation learning, or multimodal embedding systems
• Familiarity with distributed systems and large-scale data processing (Spark, Kafka, Ray, Airflow, BigQuery, Redis, etc.)
• Experience working with real-time systems and low-latency production environments
• Background in feature engineering, model optimization, and production monitoring
• Experience with LLM/Gen AI techniques, including but not limited to LLM evaluation, alignment, fine-tuning, knowledge distillation, RAG/agentic systems and productionizing LLM-powered products at scale
• Advanced degree in Computer Science, Machine Learning, or related quantitative field

Responsibilities

• Design and build production ML systems that power core experiences across the platform, including personalized recommendations, search, and ranking systems.
• Develop intelligent advertising systems including ranking, bidding, measurement, and optimization.
• Build foundational content/user representations and derive insightful signals for content, advertisers, and user understanding.
• Create large-scale machine learning pipelines, model serving infrastructure, and real-time decision systems.
• Develop applied AI and LLM-driven experiences to improve relevance, discovery, and user engagement.
• Design, build, and deploy production-grade machine learning models and systems at scale.
• Own the full ML lifecycle: from problem definition and feature engineering to 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/user understanding, and optimization systems.
• Partner cross-functionally with Product, Data Science, Infrastructure, and Engineering teams to translate complex problems into ML 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 & transformers based, and LLM evaluation/alignment.
• Contribute to technical strategy, architecture, and long-term ML roadmap.

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
• Equity in the form of restricted stock units
• Commission (depending on the position offered)
• Medical, dental, and vision insurance
• 401(k) program with employer match
• Generous time off for vacation
• Parental leave

What This Job Offers

• Job Type: Full-time
• Career Level: Senior