Senior Machine Learning Engineer, Natural Language Processing - PhD Early Career

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.

Natural Language Processing (NLP) is central to enabling massive-scale communication, creation, and safety across the Roblox platform.

This role offers the unique opportunity to build and deploy cutting‑edge NLP, speech, and generative AI models that operate at an unprecedented scale, impacting hundreds of millions of daily users.

You will solve an extremely diverse range of high‑scale language‑related problems—from real‑time moderation of voice and text to automatically localizing experiences and empowering users through LLM‑driven creation tools
. We combine cutting‑edge research with large‑scale engineering to bridge experimentation and production, designing algorithms that shape the next generation of language services for our immersive, user‑generated content platform.

• Safety AI Systems: Dedicated to building end‑to‑end ML systems for maintaining civility and safety across the platform, operating at massive scale. This includes:
  • Real‑time Moderation: Building world‑class NLP and speech models for real‑time moderation of voice and text (processing over 6 billion messages daily) and advanced interventions that measurably improve user civility.
  • Critical Harms & Advanced Detection: Developing specialized LLM agents, behavioral analysis, and graph systems for detecting and preventing rare, high‑risk scenarios (e.g., child safety, terrorism), requiring adversarial thinking and multi‑step reasoning.
  • Safety Data Quality: Ensuring all Safety AI systems are robust by managing the core data infrastructure, MLOps, and Active Learning initiatives for continuous model improvement.

You Will

• Design and implement deep learning‑based NLP and speech solutions that address problems across Roblox, from creation to safety.
• Develop advanced models, including Large Language Models (LLMs), machine translation, and generative AI
  , for user interactions, content creation, and moderation.
• Have the independence and end‑to‑end responsibility to develop NLP/ML‑based services that are scalable and resilient.
• Be a technical bar‑raiser for cutting‑edge ML technology, high code quality, and architectural designs.
• Work backward from user and product needs to deliver ML solutions that drive engagement, safety, and ecosystem growth.

You Have

• Possessing or pursuing a Ph.D. in Computer Science, Computer Engineering, Mathematics, Statistics, or a related technical field, with a thesis aligned to Roblox’s research areas.
• Expertise in one or more areas: NLP, Speech Models, Large Language Models, Machine Translation, or Generative AI (including diffusion models).
• Experience with transformer‑based model design, training, serving, and product integration.
• A strong research track record, evidenced by multiple publications and presentations in top‑tier, peer‑reviewed venues (e.g., ACL, EMNLP, Interspeech, ICML, NeurIPS).
• Proficiency in one or more programming languages (e.g., Python, C++, Go, Java) and experience building and optimizing large‑scale systems.

You may redact age, date of birth, and dates of attendance/graduation from your resume if you prefer.

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