Principal Machine Learning Engineer, Alt Defense

Overview

Technical Lead for the Alt Defense pod, architecting and building a large-scale detection system for alternate account detection and prevention, working on one of the platform's most difficult adversarial problems.

What you'll do

• Lead the technical vision for the alternate account detection platform, moving from reactive measures to proactive, near real-time prevention.
• Architect high-scale ML systems using Graph Neural Networks (GNNs) and advanced clustering techniques to map relationships across billions of entities.
• Solve complex ground truth and training data challenges for adversarial use cases.
• Build for latency and scale, ensuring detection happens within minutes of a bad actor's attempt to rejoin the platform.
• Develop innovative adversarial approaches to stay ahead of sophisticated actors who use evolving techniques to mask their identity.
• Drive the ML roadmap, identifying opportunities to leverage big data and behavioral signals to improve precision and recall in a high-stakes environment.
• Mentor and up-level a pod of high-performing ML and software engineers, fostering a culture of technical excellence and rapid iteration.
• Support additional use cases for alt detection across the company.

What you'll need

• MS or PhD degree in Computer Science, Machine Learning, or a related field.
• 10+ years of industry experience in Applied ML, with a significant focus on anti-abuse, fraud, integrity, or identity.
• Expertise in graph learning: deep experience with large-scale GNNs (GraphSAGE, PGB, etc.) and unsupervised/semi-supervised clustering at the scale of billions of nodes.
• Proven track record of leading complex technical projects from conception to production-level deployment.
• Experience with high-throughput systems: understanding of deploying ML models in low-latency environments where time-to-detect is a critical KPI.
• Adversarial mindset: ability to think like a bad actor to anticipate how they will circumvent detection and build robust defenses.

Details

• Reports to the Senior Engineering Manager of the Account Identity Team.
• Location: San Mateo, CA, United States (headquarters).
• Onsite Tuesday, Wednesday, and Thursday, with optional presence on Monday and Friday.
• Annual base salary range: $328,610 – $399,420 USD. Full-time employees are also eligible for equity compensation and benefits.
• For US-based roles only: the Company may not be able to employ candidates who have United States work authorization related to certain U.S. visa categories, or support future H-1B sponsorship at this time.