[Hiring] Staff Machine Learning Engineer @Reddit

Role Description

We are looking for a Staff Machine Learning Engineer to help drive the next generation of Reddit’s ML ecosystem across recommendations, search, messaging, and foundational AI systems. You will lead high-impact initiatives from ideation to production, shaping both technical strategy and product direction across multiple ML domains. This is a highly cross-functional role partnering with Product, Data Science, and Engineering to deliver meaningful user and business impact.

This role sits at the intersection of:

• Relevance & recommendation systems (content, search, notifications)
• AI-powered discovery & LLM-driven experiences
• Content understanding & representation
• Large-scale ML infrastructure and pipelines

If you love working on complex, real-world ML problems at massive scale, this role is for you.

What You’ll Do

• Architect, build, and deploy large-scale ML systems powering recommendations, search, messaging, and content understanding
• Lead projects from ideation → modeling → experimentation → production → iteration
• Design and improve recommender systems and ranking models across surfaces (feed, search, notifications)
• Optimize for user engagement, discovery, and long-term value
• Build next-gen AI-powered search and recommendation experiences, including LLM-integrated systems
• Develop pipelines that help users find high-quality answers and content across Reddit’s corpus
• Build and optimize content embeddings and representation models for users, communities, and content
• Leverage and advance LLMs and multimodal models for deeper understanding and personalization
• Evaluate model performance, improve accuracy, and reduce bias
• Partner with Product, Data Science, Infra, and UX teams to solve complex problems
• Translate ambiguous business needs into scalable ML solutions
• Mentor engineers and raise the bar across the organization
• Establish best practices for ML development, experimentation, and responsible AI
• Act as a thought leader across teams and domains

Qualifications

• 6+ years of experience building, deploying, and operating machine learning systems in production
• Strong programming skills in Python, Go, or similar languages, with solid software engineering fundamentals
• ML Fundamentals: a strong grasp of 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 driving measurable impact through applied machine learning

Preferred Qualifications

• Subject matter expertise in Recommender systems, search systems (lexical and semantic retrieval and ranking), advertising/auction systems, large-scale representation learning, or multimodal embedding systems, content understanding etc.
• Familiarity with distributed systems and large-scale data processing frameworks (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

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