Description
We're looking for a Senior Machine Learning Engineer to join our Ads Engineering team. As a key member of our team, you will design and build production ML systems that power core experiences across the platform, including personalized recommendations, search, and ranking systems, intelligent advertising systems, and large-scale machine learning pipelines.
Our team is responsible for building systems that operate at internet scale and directly influence user experience, advertiser value, and business outcomes. You will work on high-impact systems that improve ranking, recommendations, search relevance, prediction, content/user understanding, and optimization systems.
As a Senior Machine Learning Engineer, you will:
- 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
Basic Qualifications:
- 3-5+ years of experience building, deploying, and operating machine learning systems in production
- Strong programming skills in Python, Java, 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 improving measurable metrics through applied machine learning
Preferred Qualifications:
- Experience with recommender systems, search/ranking systems, advertising/auction systems, large-scale representation learning, or multimodal embedding systems
- Familiarity with distributed systems and large-scale data processing (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
Potential Teams:
- Ads Measurement Modeling
- Ads Targeting and Retrieval
- Advertiser Optimization
- Ads Marketplace Quality
- Ads Creative Effectiveness
- Ads Foundational Representations
- Ads Content Understanding
- Ads Ranking
- Feed Relevance
- Search and Answers Relevance
- ML Understanding
- Notifications Relevance
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
Pay Transparency:
This job posting may span more than one career level. In addition to base salary, this job is eligible to receive equity in the form of restricted stock units, and depending on the position offered, it may also be eligible to receive a commission. Additionally, Reddit offers a wide range of benefits to U.S.-based employees, including medical, dental, and vision insurance, 401(k) program with employer match, generous time off for vacation, and parental leave. To learn more, please visit https://www.redditinc.com/careers/. To provide greater transparency to candidates, we share base salary ranges for all US-based job postings regardless of state. We set standard base pay ranges for all roles based on function, level, and country location, benchmarked against similar stage growth companies. Final offer amounts are determined by multiple factors including, skills, depth of work experience and relevant licenses/credentials, and may vary from the amounts listed below. The base salary range for this position is $216,700-$303,400 USD