Machine Learning Engineer

About Us
Proofpoint is a global leader in human- and agent-centric cybersecurity. We protect how people, data, and AI agents connect across email, cloud, and collaboration tools. Over 80 of the Fortune 100, 10,000 large enterprises, and millions of smaller organizations trust Proofpoint to stop threats, prevent data loss, and build resilience across their people and AI workflows. Our mission is simple safeguard the digital world and empower people to work securely and confidently. Join us in our pursuit to defend data and protect people.
How We Work
At Proofpoint you’ll be part of a global team that breaks barriers to redefine cybersecurity guided by our BRAVE core values
Bold in how we dream and innovate
Responsive to feedback, challenges and opportunities
Accountable for results and best in class outcomes
Visionary in future focused problem-solving
Exceptional in execution and impact
Corporate Overview
Proofpoint is a leading cybersecurity company protecting organizations’ greatest assets and biggest risks vulnerabilities in people. With an integrated suite of cloud-based solutions, Proofpoint helps companies around the world stop targeted threats, safeguard their data, and make their users more resilient against cyber-attacks. Leading organizations of all sizes, including more than half of the Fortune 1000, rely on Proofpoint for people-centric security and compliance solutions mitigating their most critical risks across email, the cloud, social media, and the web.
We are singularly devoted to helping our customers protect their greatest assets and biggest security risk their people. That’s why we’re a leader in next-generation cybersecurity.
Protection Starts with People. Proofpoint.
Job Title Machine Learning Engineer
Location Sunnyvale, CA, USA, Hyderabad, A.P., India , Athens, Greece
Role Overview
Proofpoint is building the next generation of AI-powered security systems to protect organizations from rapidly evolving threats. We are looking for a highly skilled Machine Learning Engineer to help design and build production-grade ML systems that power intelligent security detections at scale. This role is focused on developing and deploying fine-tuned models that are small, fast, reliable, and cost-efficient — capable of operating in real-world, high-throughput security environments. You will work closely with security researchers, platform engineers, and product teams to turn cutting-edge ML techniques into robust detection capabilities used in production. If you enjoy optimizing models for latency, efficiency, inference cost, and operational reliability — while solving difficult security problems — we’d love to talk to you.
Key Responsibilities
Design, train, fine-tune, and evaluate machine learning models for security detection use cases
Build lightweight, high-performance models optimized for low latency, low inference cost, high throughput, operational reliability
Develop fine-tuning pipelines for LLMs and smaller transformer-based models
Experiment with techniques such as distillation, quantization, pruning, retrieval augmentation, parameter-efficient fine tuning (LoRA, adapters, etc.)
Improve detection quality while minimizing false positives and false negatives - Build scalable ML infrastructure and production inference pipelines
Partner with security researchers to transform detection logic into ML-powered systems
Measure and optimize model performance across quality, speed, memory footprint, and cost
Contribute to data engineering and labeling workflows for supervised training - Monitor production models and continuously improve robustness and reliability.
Required Qualifications
Experience 2+ years of experience in Machine Learning Engineering or Applied AI
Strong experience building and deploying ML systems in production
Experience fine-tuning transformer models or LLMs Strong Python engineering skills
Experience with modern ML frameworks such as PyTorch, Hugging Face, TensorFlow (optional)
Experience optimizing models for inference efficiency and scale
Solid understanding of model evaluation, experimentation, data pipelines, distributed training
Experience deploying models in cloud or containerized environments
Strong software engineering fundamentals and production mindset
Why Proofpoint
Protecting people is at the heart of our award-winning lineup of cybersecurity solutions, and the people who work here are the key to our success. We’re a customer-focused and a driven-to-win organization with leading-edge products. We are an inclusive, diverse, multinational company that believes in culture fit, but more importantly ‘culture-add’, and we strongly encourage people from all walks of life to apply.
We believe in hiring the best and the brightest to help cultivate our culture of collaboration and appreciation. Apply today and explore your future at Proofpoint!
Why Proofpoint?
At Proofpoint, we believe that an exceptional career experience includes a comprehensive compensation and benefits package. Here are just a few reasons you’ll love working with us
Competitive compensation
Comprehensive benefits
Career success on your terms
Flexible work environment
Annual wellness and community outreach days
Always on recognition for your contributions
Global collaboration and networking opportunities
Our Culture
Our culture is rooted in values that inspire belonging, empower purpose and drive success-every day, for everyone.
We encourage applications from individuals of all backgrounds, experiences, and perspectives. If you need accommodation during the application or interview process, please reach out to accessibility@proofpoint.com.
How To Apply
Interested? Submit your application along with any supporting information- we can’t wait to hear from you!
Consistent with Proofpoint values and applicable law, we provide the following information to promote pay transparency and equity. Our compensation reflects the cost of labor across several U.S. geographic markets, and we pay differently based on those defined markets as set out below. Pay within these ranges varies and depends on job-related knowledge, skills, and experience. The actual offer will be based on the individual candidate. The range provided may represent a candidate range and may not reflect the full range for an individual tenured employee. This role may be eligible for variable compensation and/or equity. We offer a competitive benefits package, including flexible time off, a comprehensive well-being program with two paid Wellbeing Days and two paid Volunteer Days per year, plus a three-week Work from Anywhere option.
Base Pay Ranges
SF Bay Area, New York City Metro Area
California (excludes SF Bay Area), Colorado, Connecticut, Illinois, Washington DC Metro, Maryland, Massachusetts, New Jersey, Texas, Washington, Virginia, and Alaska
All other cities and states excluding those listed above

Work arrangement
No