Senior Machine Learning Engineer - Notifications Relevance

Deliver the right content to the right user at the right time through push, email, and in-app notifications. This is a high-impact team driving DAU growth and long-term user retention by connecting users to what matters most to them. Tackle unique ML challenges at Reddit scale: recommend from hundreds of millions of posts, optimize across channels, and balance relevance, timeliness, and user fatigue. Build and productionize large-scale retrieval, ranking, and budgeting models that personalize notifications for tens of millions of users. Work across the full stack - from designing deep learning models to scaling distributed training and inference pipelines. Collaborate closely with product, data science, and infra teams to drive measurable engagement outcomes (DAU, CTR, retention). Research, prototype, and productionize retrieval and ranking models that power personalized notifications at scale. Design and build large-scale systems - from model pipelines to real-time serving - that handle Reddit’s massive user base and content volume. Drive architecture decisions and roadmap priorities for the team’s ML systems. Lead experimentation efforts, measure impact rigorously (offline + A/B), and iterate quickly. Mentor other engineers and contribute to building a high-quality, collaborative ML culture.