[2026] Senior Machine Learning Engineer, AI Platform - PhD Early Career

Roblox is a platform that enables millions of users to create and share immersive 3D experiences. They are seeking aSenior Machine Learning Engineer to contribute to building cutting-edge AI systems, focusing on AI platform projects, distributed inference systems, and information retrieval for generative AI. Responsibilities Pioneer next-generation AI tooling to enhance the efficiency, bolthires, and usability of ML@Roblox Build and maintain core platform components: Serving Layer, Model Registry, Pipeline Orchestrator, and Training/Inference control planes Design great developer experiences (paved-road templates, tooling, visualizations) to reduce time-to-production and ensure foundational AI systems are scalable and reliable Architect and implement scalable distributed inference systems for efficiently serving LLMs and Large Recommender Models at massive scale Conduct deep, low-level performance analysis and optimize ML models (using techniques like continuous batching, speculative decoding, and quantization) and systems on GPU architectures to maintain peak performance and stability Lead the design and development of Retrieval-Augmented Generation (RAG) systems Build and maintain core information retrieval infrastructure—vector databases and knowledge graphs—to enable accurate grounding of Gen AI models Ship language models and 3D objects as a service for the Roblox community, making creation easier Skills 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 Experience with high performance distributed systems, ML Infrastructure, LLM fine tuning/RL, Information Retrieval and Gen AI context generation Expertise in one or more of the following key areas: AI/ML Platform Data stores - Features stores, Vector DBs and Knowledge Graphs Expertise in LLMs - Fine tuning, Safety Expertise in Agentic systems - Agent evaluation, context engineering Experience building agentic applications with context for real world applications Collaborative mindset and experience integrating and deploying optimized models with cross-functional teams, including data scientists and software engineers Experience with graph databases and large-scale GNNs (Graph Neural Networks) Experience working with Kubernetes Experience working with one or more cloud providers (e.g., AWS, Azure, GCP) Experience working with high availability systems Experience working with ML models, LLMs or other AI systems Benefits Equity compensation Benefits as described on this page Company Overview Roblox is an online gaming and entertainment platform that offers a shared digital experience that brings people together through play.It was founded in 2004, and is headquartered in San Mateo, California, USA, with a workforce of 1001-5000 employees. Its website is Company H1B Sponsorship Roblox has a track record of offering H1B sponsorships, with 240 in 2025, 111 in 2024, 139 in 2023, 153 in 2022, 91 in 2021, 92 in 2020. Please note that this does not guarantee sponsorship for this specific role.