Staff ML Engineer, Ads Retrieval (Remote)

Fdetimes; United States; Remote; USD 230,000 - 322,000; Full time

Benefits offered by this job

Remote work

Healthcare benefits

401k with employer match

Paid parental leave

Mental health support

Flexible vacation

Job summary

Reddit is seeking a Staff Machine Learning Engineer to lead the Retrieval ML team and shape the design of retrieval models at Reddit scale. You will guide candidate generation, embeddings, and end-to-end product impact across ads surfaces while mentoring engineers and setting long-term technical direction.

You will work from a fully remote environment with awareness of US-based salary ranges and equity opportunities, collaborating with cross-functional partners to deliver measurable improvements

Qualifications

• 7+ years of industry experience, including substantial experience building and shipping applied ML products.
• Deep experience with information retrieval, candidate generation, recommender systems, ranking, or related relevance problems.
• Strong understanding of retrieval modeling concepts, including DNN, embeddings, two-tower or dual-encoder models, approximate nearest-neighbor search, and multi-stage retrieval.
• Deep experience training, evaluating, debugging, and deploying deep learning models using TensorFlow, PyTorch, or similar frameworks.
• Demonstrated ownership of ML projects from problem framing and data preparation through offline evaluation, online experimentation, production launch, and iteration.
• Strong command of experimental design and model evaluation, including how offline retrieval metrics relate to downstream business and user metrics.
• Experience working with large-scale behavioral, contextual, or content datasets and complex feature pipelines.
• Strong software engineering fundamentals and the ability to write clear, reliable maintainable production code.
• Technical leadership experience: setting direction, leading complex projects, influencing partner teams, and mentoring other engineers.
• Excellent written and verbal communication, with the ability to explain complex modeling choices to technical and non-technical audiences.

Responsibilities

• Define the technical direction and multi-year roadmap for ads retrieval modeling in partnership with engineering, product, data science, and ads stakeholders.
• Design, develop, and launch candidate-generation and retrieval models for campaigns and ads across Reddit’s advertising surfaces.
• Apply modern approaches such as two-tower architectures, representation learning, embeddings, sequence models, graph-based methods, and other deep learning techniques when they create meaningful product value.
• Improve the retrieval stack across key modeling decisions, including objectives, labels, sampling strategies, hard-negative mining, feature design, embedding generation, candidate filtering, and retrieval depth.
• Work with approximate nearest-neighbor and vector retrieval systems, reasoning about recall, relevance, freshness, diversity, coverage, latency, and cost trade-offs.
• Establish strong evaluation practices that connect retrieval metrics—such as recall, precision, candidate coverage, calibration, and downstream lift—to ads and user outcomes.
• Lead offline analysis and online experiments, interpret ambiguous results, and translate findings into the next modeling iteration.
• Partner with downstream ranking, ads platform, auction, measurement, and product teams to ensure retrieval models integrate effectively into the full ads funnel.
• Write design documents, review code and model changes, and raise the quality bar for modeling, testing, observability, and production ownership.
• Mentor ML engineers and help grow the team’s expertise in retrieval, recommendation, and representation learning.

Skills

Information retrieval

Recommender systems

Two-tower models

TensorFlow

PyTorch

Experiment design

Leadership

Tools

TensorFlow

PyTorch

Job description

Reddit is seeking a Staff Machine Learning Engineer to lead the Retrieval ML team and shape the design of retrieval models at Reddit scale. You will guide candidate generation, embeddings, and end-to-end product impact across ads surfaces while mentoring engineers and setting long-term technical direction.

You will work from a fully remote environment with awareness of US-based salary ranges and equity opportunities, collaborating with cross-functional partners to deliver measurable improvements