Principal ML Solutions Architect - Token Factory

About Nebius: Nebius is leading a new era in cloud infrastructure for the global AI economy. We are building a full-stack AI cloud platform that supports developers and enterprises from data and model training through to production deployment, without the cost and complexity of building large in-house AI/ML infrastructure. Built by engineers, for engineers. From large-scale GPU orchestration to inference optimization, we own the hard problems across compute, storage, networking and applied AI. Listed on Nasdaq (NBIS) and headquartered in Amsterdam, we have a global footprint with R&D hubs across Europe, the UK, North America and Israel. Our team of 1,500+ includes hundreds of engineers with deep expertise across hardware, software and AI R&D. The role This position sits within Nebius Token Factory , our serverless platform for running and customizing open-source LLMs in production. Token Factory allows for serverless inference and fine-tuning ( LoRA , full FT , RFT ) backed by in-house optimizations like custom speculative decoding, quantization, cache-aware routing and dedicated endpoints. Customers come to us to move from prototype to scaled production without the cost and complexity of building and tuning their own inference stack. We're looking for a Principal ML Solutions Architect to act as the most senior technical authority for customers leveraging Token Factory's serverless inference and fine-tuning platforms. Beyond designing and implementing optimized inference and fine-tuning workflows, you will set technical direction across our largest and most strategic accounts, own the hardest performance and quality problems end to end, mentor other Solutions Architects, and serve as a primary technical voice shaping the platform roadmap with backend, product, and research teams. You’re welcome to work remotely from the United States . Your responsibilities will include: • Own the most complex, highest-stakes customer engagements from architecture through production across multiple modalities, driving measurable business value • Optimize LLM inference at the framework and hardware level and codify the resulting best practices into reusable playbooks for the team • Lead supervised and reinforcement fine-tuning efforts to maximize model quality • Design and implement production-ready LLM solutions using Token Factory's inference services • Provide deep technical expertise in prompt engineering, RAG architectures, model selection, and cost/performance trade-offs at scale • Partner closely with product, engineering and research to surface customer needs, prototype platform features, and directly influence the roadmap • Guide customers from PoC to production with a focus on performance, reliability, and cost efficiency — and define the standards by which the team does so • Mentor Senior and mid-level Solutions Architects; raise the technical bar of the team through review, enablement, and knowledge sharing • Represent Token Factory externally through talks, blog posts, and conferences We expect you to have: • 8+ years of experience in ML/AI systems, with at least 4 years focused on LLMs and generative AI • Demonstrated technical leadership : owning ambiguous, high-impact problems end to end and influencing decisions across teams and customers • Expert knowledge of the LLM ecosystem : model architectures, fine-tuning approaches, and inference internals • Deep, hands-on command of inference optimization : quantization, KV -cache management, batching, routing, etc. • Hands-on experience with: • Running LLMs in production at scale : deploying, operating, and debugging inference workloads down to the framework level • LLM fine-tuning , including SFT / LoRA and data preparation/curation; experience with RL -based fi