Staff / Principal Applied ML Engineer (Search & Retrieval) at Nebius

Why work at Nebius Nebius is leading a new era in cloud computing to serve the global AI economy. We create the tools and resources our customers need to solve real-world challenges and transform industries, without massive infrastructure costs or the need to build large in-house AI/ML teams. Our employees work at the cutting edge of AI cloud infrastructure alongside some of the most experienced and innovative leaders and engineers in the field. Where we work Headquartered in Amsterdam and listed on Nasdaq, Nebius has a global footprint with R&D hubs across Europe, North America, and Israel. The team of over 1400 employees includes more than 400 highly skilled engineers with deep expertise across hardware and software engineering, as well as an in-house AI R&D team. We are seeking a Staff / Principal Applied ML Engineer to design and own large-scale machine learning systems powering an agent-native search platform - the emerging web access layer for AI. You will operate end-to-end, from research-grade ideas to production systems, solving hard problems across retrieval, ranking, and indexing in high-throughput, low-latency environments. Your responsibilities: • Own end-to-end ML systems from problem definition to production and iteration • Design and deploy models for retrieval, reranking, and search relevance • Build and optimise large-scale embedding-based retrieval and indexing systems • Develop query understanding, rewriting, and iterative retrieval pipelines • Drive measurable improvements in relevance, latency, and cost • Define and evolve evaluation frameworks and quality metrics • Operate systems under strict low-latency, high-throughput constraints • Collaborate closely with engineering and infrastructure teams to ship production systems • Contribute to system architecture and long-term technical direction • Raise the technical bar through leadership and mentorship Must-haves: • 8+ years of experience in software engineering or applied machine learning • Proven ownership of large-scale ML systems in production end-to-end • Strong programming skills in Python and at least one of Go or C++ • Deep experience in one or more of: search, recommendation systems, ads ranking • Hands-on experience with retrieval, ranking, or matching systems • Experience operating high-throughput, low-latency production systems • Strong understanding of modern ML (embeddings, transformers, ranking models) • Experience designing evaluation frameworks and meaningful metrics • Ability to operate in ambiguity and drive problems end-to-end • Track record of making trade-offs between quality, latency, and cost Nice to haves: • Experience with RAG, LLM-integrated systems, or agent-based architectures • Experience with large-scale indexing, crawling, or data pipelines • Familiarity with hybrid search (lexical and semantic) • Experience with personalization or user modelling • Contributions to open-source, publications, or technical talks We conduct coding interviews as part of the process. What we offer • Competitive salary and comprehensive benefits package. • Opportunities for professional growth within Nebius. • Flexible working arrangements. • A dynamic and collaborative work environment that values initiative and innovation. We’re growing and expanding our products every day. If you’re up to the challenge and are excited about AI and ML as much as we are, join us!