Senior Machine Learning Engineer

Reddit is a community of communities. It’s built on shared interests, passion, and trust, and is home to the most open and authentic conversations on the internet. Every day, Reddit users submit, vote, and comment on the topics they care most about. With 100,000+ active communities and approximately 130 million daily active unique visitors, Reddit is one of the internet’s largest sources of information. For more information, visit www.redditinc.com .

At Reddit, machine learning sits at the heart of how millions of people discover, connect, and engage with the world’s largest collection of human conversations. From powering personalized recommendations and search to optimizing advertising systems and marketplace dynamics, our ML engineers tackle some of the most interesting and impactful problems in large-scale applied machine learning.

We hire Machine Learning Engineers across both our Consumer and Ads organizations, giving you the opportunity to work on a wide range of high-impact problems across the Reddit ecosystem.

We are looking for Machine Learning Engineers who are excited to build systems end-to-end, from research and modeling to production deployment, — and who want to help shape the future of discovery, relevance, and monetization at Reddit.

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

What You’ll Work On

As a Machine Learning Engineer at Reddit, you will design and build production ML systems that power core experiences across the platform, including:

Personalized recommendations, search, and ranking systems that help users discover the most relevant content and communities

Intelligent advertising systems including ranking, bidding, measurement, and optimization

Content, Advertisers, and User understanding, from building foundational content/user representations to deriving insightful signals

Large-scale machine learning pipelines, model serving infrastructure, and real-time decision systems

Applied AI and LLM-driven experiences that improve relevance, discovery, and user engagement

You’ll work on high-impact systems that operate at internet scale and directly influence user experience, advertiser value, and business outcomes.

What You’ll Do

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

Basic Qualifications

3-5+ years of experience building, deploying, and operating machine learning systems in production