Staff Machine Learning Engineer

Summary

Join Reddit's LS Embedding Team as a Staff Machine Learning Engineer and lead the development of next-generation multi-entity embeddings. You will define and execute the ML strategy for embedding models, enhancing personalization and recommendation quality. Lead research initiatives on scalable graph-based learning and bring cutting-edge advancements into production. Partner with infrastructure teams to build high-performance training systems and optimize real-time serving architectures. Collaborate with cross-functional teams and mentor other engineers. This role requires extensive experience in machine learning engineering, particularly in representation learning and large-scale embeddings.

Requirements

• 8+ years of experience in machine learning engineering, with a strong focus on representation learning, large-scale embeddings, and recommendation systems
• Expertise in Graph Neural Networks (GNNs), graph-based representation learning, and transformer architectures
• Deep understanding of graph theory, knowledge graphs, and complex multi-entity relationships in machine learning applications
• Proven ability to design, implement, and optimize scalable ML architectures, from distributed training to real-time inference
• Hands-on experience with PyTorch Geometric (PyG), Deep Graph Library (DGL), TensorFlow, JAX, and large-scale ML model optimization
• Strong software engineering skills in Python, C++, or similar languages, with experience in ML infrastructure, high-performance computing, and cloud-based ML pipelines
• Demonstrated leadership in driving ML strategy, mentoring engineers, and influencing cross-functional teams
• Experience with A/B testing, model evaluation frameworks, and real-time feedback loops in large-scale production systems
• Excellent communication skills, with the ability to effectively present complex ML concepts to technical and non-technical stakeholders

Responsibilities

• Architect and lead the development of next-generation multi-entity embeddings, leveraging Graph Neural Networks (GNNs), transformers, and large-scale representation learning techniques
• Define and execute the ML strategy for embedding models, identifying opportunities to enhance personalization and recommendation quality across Reddit
• Lead research initiatives on scalable graph-based learning, self-supervised techniques, and real-time adaptation, bringing cutting-edge advancements into production
• Partner with ML infrastructure teams to build high-performance, distributed training systems that efficiently scale across multiple GPUs and cloud environments
• Establish and optimize real-time serving architectures for large-scale embeddings, ensuring low-latency inference and high throughput
• Collaborate cross-functionally with teams in Feed Ranking, Ads, Content Understanding, and Core ML to integrate embeddings into Reddit’s key AI-driven systems
• Mentor and guide senior and mid-level ML engineers, fostering a culture of excellence, innovation, and knowledge sharing
• Stay at the forefront of AI research, evaluating and introducing new modeling paradigms to keep Reddit’s ML ecosystem at the cutting edge
• Drive technical discussions, present findings to leadership, and contribute to long-term ML planning and decision-making

Benefits

• Comprehensive Healthcare Benefits and Income Replacement Programs
• 401k Match
• Family Planning Support
• Gender-Affirming Care
• Mental Health & Coaching Benefits
• Flexible Vacation & Reddit Global Days off
• Generous paid Parental Leave
• Paid Volunteer time off
• Medical, dental, and vision insurance
• 401(k) program with employer match
• Generous time off for vacation
• Parental leave