Senior ML Engineer for Ads Retrieval & Targeting

ContentBuffer; United States; Remote; USD 180,000 - 260,000; Full time

Job summary

Reddit is seeking a Staff Machine Learning Engineer to lead the Ads Retrieval ML team. You will steer retrieval model design, experimentation, and impact at Reddit scale. Expect hands-on work from data design to production, with mentoring of engineers and cross-functional collaboration with product and ads teams.

You will guide candidate-generation, retrieval strategies, and advanced modeling approaches, balancing recall, relevance, and latency while delivering measurable product outcomes.

Qualifications

• 7+ years delivering applied ML products in industry.
• Deep experience with information retrieval and candidate generation.
• Expertise in retrieval modeling concepts and multi-stage retrieval.
• Strong experience training, evaluating, debugging, and deploying DL models with TensorFlow or PyTorch.
• Ownership of ML projects from problem framing to production launch.
• Strong experimental design and understanding of offline vs online metrics.
• Experience with large-scale behavioral datasets and complex feature pipelines.
• Excellent software engineering fundamentals and production-grade code.

Responsibilities

• Define the technical direction and multi-year roadmap for ads retrieval modeling.
• Design, develop, and launch candidate-generation and retrieval models across Reddit surfaces.
• Apply advanced techniques like two-tower architectures, embeddings, and graph methods.
• Improve retrieval stack decisions: objectives, sampling, hard negatives, features, and depth.
• Collaborate on recall, relevance, latency, cost trade-offs with NN search systems.
• Establish evaluation practices linking retrieval metrics to ads and user outcomes.
• Lead offline analysis, online experiments, and translate findings to iterations.
• Partner with downstream ranking and ads platform teams for integration.
• Mentor engineers and raise the team's expertise in retrieval and representation learning.

Skills

Staff-level leadership

Information retrieval

Recommender systems

DNN / embeddings

NN search / ANN

TensorFlow / PyTorch

Model evaluation & experimentation

Production ML engineering

Large-scale systems

Technical leadership

Code quality / testing

Cross-functional collaboration

Tools

TensorFlow

PyTorch

Index/ANN systems

Job description

Reddit is seeking a Staff Machine Learning Engineer to lead the Ads Retrieval ML team. You will steer retrieval model design, experimentation, and impact at Reddit scale. Expect hands-on work from data design to production, with mentoring of engineers and cross-functional collaboration with product and ads teams.

You will guide candidate-generation, retrieval strategies, and advanced modeling approaches, balancing recall, relevance, and latency while delivering measurable product outcomes.