Senior ML Engineer: Ads Retrieval & Targeting (Remote)

Reddit, Inc.; San Francisco (CA); Remote; USD 230,000 - 322,000; Full time

Benefits offered by this job

Remote work

Healthcare benefits

401k with employer match

Global benefits

Family planning support

Gender-affirming care

Mental health & coaching

Flexible vacation

Paid parental leave

Job summary

Reddit, Inc. is seeking a Staff Machine Learning Engineer to lead retrieval modeling for ads. You will guide the design of retrieval models, candidate generation, and cross-team collaboration to improve relevance and advertiser outcomes at scale.

This applied ML role emphasizes end-to-end impact, including experimentation, deployment, and mentoring other engineers. Competitive salary, equity, and comprehensive benefits accompany this opportunity.

Qualifications

• 7+ years of industry experience building and shipping applied ML products.
• Deep experience with information retrieval, candidate generation, and ranking.
• Strong knowledge of retrieval modeling concepts: DNNs, embeddings, two-tower models, ANN search.
• Experience training and deploying DL models using TensorFlow, PyTorch, or similar.
• Ownership of ML projects from data prep to production launch and iteration.
• Strong experimental design and evaluation linking offline metrics to business/User outcomes.
• Experience with large-scale datasets and complex feature pipelines.
• Solid software engineering fundamentals; ability to write reliable production code.
• Technical leadership: setting direction, leading projects, mentoring engineers.
• Excellent written and verbal communication for technical and non-technical audiences.

Responsibilities

• Define the technical direction and multi-year roadmap for ads retrieval modeling with cross-functional partners.
• Design, develop, and launch candidate-generation and retrieval models across Reddit's ad surfaces.
• Apply modern approaches (two-tower, embeddings, sequence models, graph methods) when valuable.
• Improve retrieval stack decisions: objectives, labels, sampling, hard negatives, features, embeddings.
• Work with ANN and vector retrieval systems, balancing recall, relevance, latency and cost.
• Establish evaluation practices linking retrieval metrics to ads and user outcomes.
• Lead offline analyses and online experiments; translate results into iterative modeling improvements.
• Partner with ranking, ads platform, auction, measurement and product teams for integration.
• Write design docs, review code, raise quality standards for modeling, testing, observability, ownership.
• Mentor ML engineers and grow expertise in retrieval, recommendation, and representation learning.

Skills

7+ years experience

Information retrieval

DNN embeddings

Two-tower/dual-encoder

TensorFlow/PyTorch

ML project ownership

Experiment design

Large-scale data handling

Production-grade code

Technical leadership

Communication skills

Job description

Reddit, Inc. is seeking a Staff Machine Learning Engineer to lead retrieval modeling for ads. You will guide the design of retrieval models, candidate generation, and cross-team collaboration to improve relevance and advertiser outcomes at scale.

This applied ML role emphasizes end-to-end impact, including experimentation, deployment, and mentoring other engineers. Competitive salary, equity, and comprehensive benefits accompany this opportunity.