Jobs / United States / Roblox Corporation
Principal Machine Learning Engineer, Alt Defense
Roblox Corporation · 🇺🇸 San Mateo, CA, United States
Sponsorship verdict
Sponsorship possible
One solid signal, not two — worth applying, and worth asking about sponsorship early.
- Employer is on a government sponsor recordThe US Department of Labor certified 197 H-1B/E-3 labor condition applications for this employer between Oct 2025 and Jun 2026 (latest Jun 2026) — the step every H-1B hire needs first. USCIS also records 48 H-1B approvals in FY2023. Source: LCA disclosure data (US Department of Labor (OFLC)).
- The posting doesn’t mention sponsorshipSilence isn’t a refusal — ask the recruiter before investing much time.
- No salary bar for this routeH-1B has no fixed salary bar: the employer must pay at least the prevailing wage for the role and area. Cap-subject employers enter a lottery weighted by wage level. Source: https://www.federalregister.gov/documents/2025/12/29/2025-23853/weighted-selection-process-for-registrants-and-petitioners-seeking-to-file-cap-subject-h-1b, rules effective 2026-02-27.
- What Roblox Corporation paid sponsored hires in similar roles122 certified filings for “Senior Software Engineer” (Software Developers) in CA: $227k–$295k, median $243k. Most were filed at wage level IV (41%) — 4 lottery entries, ≈61% projected selection odds for cap-subject employers. Source: US Department of Labor LCA disclosure data (Oct 2025 – Jun 2026).
- Confirmed live todayWhen a source last listed this job as open.
US H-1B: cap-subject employers enter a lottery weighted by wage level — Level I gets 1 entry, Level IV gets 4 (DHS projected selection odds ≈15% at Level I to ≈61% at Level IV). Universities and non-profit research employers are cap-exempt. The $100,000 fee for new petitions from abroad is currently blocked by a court order (appeal pending).
A verdict summarises public evidence; it is not legal advice and never a guarantee — the employer and the immigration authority decide. Sign in to factor in where you can already work.
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Sponsor Radar — Roblox Corporation
The US Department of Labor certified 197 H-1B/E-3 labor condition applications for this employer between Oct 2025 and Jun 2026 (latest Jun 2026) — the step every H-1B hire needs first. USCIS also records 48 H-1B approvals in FY2023. Source: LCA disclosure data (US Department of Labor (OFLC)).
Past sponsorship or register membership never guarantees sponsorship for this vacancy or for you. Full Sponsor Radar for Roblox Corporation →
About the role
Every day, tens of millions of people come to Roblox to explore, create, play, learn, and connect with friends in 3D immersive digital experiences– all created by our global community of developers and creators. At Roblox, we’re building the tools and platform that empower our community to bring any experience that they can imagine to life. Our vision is to reimagine the way people come together, from anywhere in the world, and on any device. We’re on a mission to connect a billion people with optimism and civility, and looking for amazing talent to help us get there. A career at Roblox means you’ll be working to shape the future of human interaction, solving unique technical challenges at scale, and helping to create safer, more civil shared experiences for everyone. WHY SAFETY? At Roblox, we strive to connect a billion people with optimism and civility, and the Safety organization’s mission is to become the leader in civil immersive online communities. We systematically detect, remove, and prevent problematic accounts, content and behavior, and we make Roblox accounts secure and free from compromise. We cover a broad area of the tech spectrum, including machine learning, classifiers for 3D models, experimentation, automation, detection workflows, and AI-powered text filters. Aligned and partnering with product teams, we use this toolbelt to discover new opportunities, influence and shape the product roadmap and prioritization, build safety products, and measure the impact on our community of users and developers. In doing so, we keep Roblox safe, civil, and inclusive, and we foster positive relationships between people around the world. WHY ALT DEFENSE? Safety and Civility is Roblox’s #1 priority. The Alt Defense pod is at the front lines of this mission, tasked with solving one of the most difficult adversarial problems on the platform: Alternate Account Detection and Prevention. When bad actors are removed from Roblox, they often attempt to return immediately with new identities. Our goal is to stop them in their tracks. As the Technical Lead for this pod, you will architect and build an industry-leading detection system that operates at a massive scale—processing billions of accounts and identifying recidivism within minutes. You will also be supporting additional use cases for alt detection across the company. You will report to the Senior Engineering Manager of the Account Identity Team. You will: • Lead the technical vision for 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 usecases • Build for latency and scale, ensuring that 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. You have: • 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 reco