Reddit is looking for a Senior Machine Learning Engineer to join the Notifications Relevance team to deliver the right content to the right user at the right time through push, email, and in-app notifications, aiming to drive DAU growth and long-term user retention.
Requirements
- 5+ years of industry experience (post-internship) working on large-scale machine learning systems.
- Hands-on experience building, deploying, and scaling recommender systems (retrieval + ranking) in production.
- Deep understanding of system-level trade-offs in large-scale recommendation pipelines (e.g. latency, throughput, storage of embeddings, feature freshness).
- Proficiency in Python; familiarity with frameworks like PyTorch or TensorFlow.
- Experience with distributed training and inference using tools like Ray, PyTorch Distributed, or similar.
- Experience developing sequential modeling and real-time systems.
- Familiarity with reinforcement learning or multi-objective optimization in recommendation systems.
Responsibilities
- 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.
- 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).
Other
- Mentor other engineers and contribute to building a high-quality, collaborative ML culture.
- 100% remote, and open only to candidates currently located within the United States.
- Reddit is proud to be an equal opportunity employer, and is committed to building a workforce representative of the diverse communities we serve.
- Reddit is committed to providing reasonable accommodations for qualified individuals with disabilities and disabled veterans in our job application procedures.
- If, due to a disability, you need an accommodation during the interview process, please let your recruiter know.
