# Senior Machine Learning Engineer, Ads

**Company:** [Reddit](https://hotfix.jobs/companies/reddit)
**Location:** Remote
**Role:** ML Engineering
**Salary:** $217k – $303k/yr
**Experience:** 5+ years
**Skills:** Python, Java, Go, PyTorch, TensorFlow, Xgboost, Transformers, Cnns, Gnns, Spark, Kafka, Ray, Airflow, BigQuery, Redis
**Posted:** 2026-06-16

> Design, build, and deploy production ML systems for recommendations, search, ranking, and advertising at internet scale. Own the full ML lifecycle from modeling to monitoring with strong cross-functional collaboration.

## Job Description

## 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

## 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
- 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

## 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

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**Apply:** https://hotfix.jobs/jobs/38a90e06-7152-474a-aaf0-bd106f198aee
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