[2026] Senior Machine Learning Engineer, Natural Language Processing - PhD Early Career

Roblox • San Mateo, CA

32d

About The Position

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. Teams Hiring for This Role 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.

Requirements

• 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.

Responsibilities

• 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.

What This Job Offers

• Job Type: Full-time
• Career Level: Senior
• Industry: Administrative and Support Services
• Education Level: Ph.D. or professional degree
• Number of Employees: 1,001-5,000 employees