Machine Learning Engineer Intern Jobs in Cupertino, CA

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, safeguardtheir 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 criticalrisks 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 lookingfor 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, andcost-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 inproduction. 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 machinelearning 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 infrastructureand 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 workflowsfor 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 MLsystems 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! #LifeAtProofpoint

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: