Staff Machine Learning Engineer, AI Security
About this role
Developing, training, and optimizing models for AI security constitutes the core daily focus for the new hire at Reddit. Operating within the Security Platform Engineering organization, the team builds foundational security into internal engineering systems, operational infrastructure, and AI products like the centralized LLM Guardrails Platform. Engineers in this function design practical machine learning solutions that actively detect and prevent prompt injection, jailbreaks, sensitive data exposure, and unauthorized agent behavior.
As a founding Staff Machine Learning Engineer, the person in this seat takes charge of model architecture, training data curation, and cross-functional technical leadership. The mandate involves expanding ML-powered protections while safeguarding the overall product experience for millions of daily active visitors. Ideal candidates bring extensive background in deep learning combined with strategic vision to establish long-term modeling roadmaps and mentor engineering peers.
What you will do
- Select, adapt, fine-tune, evaluate, and deploy pretrained models and lightweight classifiers to solve Reddit-specific security challenges.
- Build reproducible training and evaluation pipelines in partnership with platform engineers to optimize inference performance and resource efficiency.
- Set the technical vision and multi-quarter modeling roadmap while collaborating with cross-functional partners to define architecture requirements.
- Conduct thorough model evaluations and performance analyses to balance accuracy, adversarial robustness, latency, throughput, reliability, and cost.
- Manage training-data quality and oversee the production model lifecycle using monitoring insights, incident findings, and red-team feedback.
- Establish rigorous best practices for responsible machine learning development, encompassing data lineage, privacy-aware usage, and testing.
What you need
- Bring 8 or more years of professional experience developing machine learning models with substantial hands-on model training and production impact.
- Demonstrate strong proficiency in Python programming, software engineering, and deep learning frameworks such as TensorFlow, PyTorch, or Hugging Face Transformers.
- Possess a deep understanding of neural network architectures, optimization, data preprocessing, tokenization, embeddings, and model calibration.
- Show expertise in scalable data pipelines and distributed training frameworks like Ray Train or PyTorch Distributed alongside system tradeoffs.
- Apply rigorous experimental design and model evaluation methods, including holdouts, ablation studies, adversarial tests, and error analysis.
- Communicate clearly and effectively in writing and speech to explain complex model behavior, security risks, and technical tradeoffs to diverse partners.
Nice to have
- Experience applying ML to security, trust and safety, fraud, privacy, or related adversarial domains.
- Experience with adversarial training, model distillation, active learning, or synthetic-data generation.
Benefits
- Comprehensive Healthcare Benefits and Income Replacement Programs
- 401k with Employer Match
- Global Benefit programs for workspace, professional development, and caregiving support
- Family Planning Support and Gender-Affirming Care
- Mental Health and Coaching Benefits
- Flexible Vacation, Paid Volunteer Time Off, and Generous Paid Parental Leave
Skills and tech stack
Questions candidates ask
What is the remote work policy for this position?
The role is fully remote within the United States. Candidates can work from approved U.S. remote locations.
What is the salary range for the Staff Machine Learning Engineer role?
The base salary range for this position is $230,000 to $322,000 USD. In addition to base pay, the role is eligible to receive equity in the form of restricted stock units.
What team does this role belong to?
This position sits on the AI Security team within Reddit’s Security Platform Engineering organization. The group builds security into Reddit products, engineering systems, AI platforms, and operational infrastructure.
What tools and frameworks are used in the tech stack?
Engineers work with Python, deep learning frameworks such as TensorFlow, PyTorch, and Hugging Face Transformers, as well as distributed training tools like Ray Train and PyTorch Distributed.