Reddit, Inc. · 2 days ago
Senior Machine Learning Engineer, GenAI Security
United States
Full-time
Remote
Senior Level
$217K/yr - $303K/yr
5+ years expReddit is a community of communities that fosters open and authentic conversations on the internet. The Senior Machine Learning Engineer will lead model development for GenAI Security, focusing on building high-quality ML models to detect and prevent security risks associated with AI traffic.
Social MediaConsumer GoodsDigital MediaPublishingCommunitiesConsumerContentNewsSocial Network
Responsibilities
Build and improve security-focused ML models for Reddit’s GenAI traffic, including guardrail models, semantic classifiers, anomaly detection models, and other neural network based security signals
Own model development end to end: define the security problem, assemble and label datasets, build ETL pipelines, engineer features, train models, evaluate quality, deploy to production, monitor performance, and retrain from production feedback
Use modern deep learning architectures, including neural networks, transformers, sequence models, embeddings, and model distillation where they are the right practical fit
Design rigorous evaluation suites for adversarial examples, hard negatives, long-context inputs, structured payloads, tool calls, multi-turn workflows, and real production traffic
Improve model precision, recall, latency, cost, calibration, and operational reliability for high-impact production surfaces
Build repeatable MLOps workflows for SPACE, including training pipelines, model lineage, artifact management, holdout evaluation, dashboards, rollback paths, and retraining loops
Partner closely with ML Infrastructure, LLM Gateway, DevX, Ads, Answers, Safety, Privacy, Compliance, and other Security teams to bring security models into real production workflows
Work pragmatically with Reddit’s evolving ML platform, using existing infrastructure where possible and building focused tooling when needed to keep model iteration moving
Translate security goals into measurable model outcomes and help partners understand tradeoffs between risk reduction, latency, false positives, and product impact
Provide technical direction to other engineers and serve as a go-to ML expert for GenAI Security and broader SPACE model needs
Qualification
Required
5+ years of experience building, training, evaluating, and deploying production ML or deep learning models
Hands-on experience with modern ML frameworks such as PyTorch, TensorFlow, or similar
Strong practical understanding of the full ML lifecycle: problem definition, data ETL, feature engineering, training, evaluation, deployment, monitoring, debugging, and retraining
Experience building data pipelines and working with large-scale datasets
Experience designing rigorous model evaluations, including precision/recall/F1, false positive analysis, threshold tuning, calibration, holdout sets, regression tests, and production-quality validation
Experience shipping production-quality software, preferably in Python and/or Go
Strong communication skills and ability to explain model behavior, risk tradeoffs, and technical decisions to cross-functional partners
BS degree in Computer Science, Machine Learning, a related technical field, or equivalent practical experience
Preferred
Applying ML to security, privacy, trust and safety, abuse prevention, adversarial ML, or GenAI security problems
Training or fine-tuning neural text models for complex inputs such as long-context prompts, structured payloads, code-like content, multi-turn interactions, or tool calls
Production MLOps or model serving systems such as Airflow, Ray, MLflow, Triton, ONNX, Kubernetes, or similar
Improving model quality through labeling strategy, hard-negative mining, synthetic data generation, distillation, or active learning
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
Company
Reddit, Inc.
Reddit is the heart of the internet, where millions of people get together to talk about any topic imaginable.
1001-5000 employees
H1B Sponsorship
Reddit, Inc. has a track record of offering H1B sponsorships. Please note that this does not
guarantee sponsorship for this specific role. Below presents additional info for your
reference. (Data Powered by US Department of Labor)
Distribution of Different Job Fields Receiving Sponsorship
84%
Represents job field similar to this job
Engineering and Development
Product Management
Management and Executive
Marketing
Creatives and Design
Sales
Customer Service and Support
Accounting and Finance
Trends of Total Sponsorships
*2026 (35)
2025 (99)
2024 (63)
2023 (76)
2022 (70)
2021 (68)
2020 (39)
Funding
Current Stage
Public CompanyTotal Funding
$1.33BKey Investors
FidelityVy CapitalTencent
2024-03-21IPO
2021-08-12Series F· $410M
2021-02-08Series E· $367.95M
Leadership Team
Steve Huffman
CEO
Andrew Vollero
Chief Financial Officer
Recent News
Benzinga.com
2026-07-20
2026-07-16
Company data provided by crunchbase