[Hiring] Staff / Principal Applied AI Researcher @Nebius

Role Description

Nebius is seeking a Staff or Principal Applied AI Researcher to join a fast-growing team building an agent native search platform - the web access layer for AI systems. This role involves:

• Designing agent native retrieval systems optimized for machine consumption rather than human search UX.
• Building systems where LLMs iteratively plan, query, refine, and reason over results.
• Developing ranking and retrieval approaches for multi-step, agent-driven workflows under real-world constraints.

Your responsibilities will include:

• Driving applied research and technical direction across retrieval and ranking systems.
• Designing and evolving multi-stage retrieval architectures (query understanding, rewriting, reranking, iterative retrieval).
• Developing methods for grounding LLMs in real-time web data at scale.
• Defining and implementing new evaluation paradigms and metrics for agentic systems, where correctness is not reducible to clicks.
• Leading experimentation on modern retrieval approaches (embeddings, hybrid search, reranking) and bringing them into production.
• Analyzing trade-offs across relevance, latency, and cost at scale.
• Working closely with engineering to deploy systems in high throughput, low latency environments.
• Owning ambiguous problems end to end and contributing to product and research direction.
• Mentoring engineers and helping raise the technical bar of the team.

Qualifications

• 8+ years of experience in applied AI, ML, or software engineering.
• Proven track record of shipping ML or AI systems to production at scale.
• Deep experience with search, retrieval, ranking, recommendation systems, or assistants.
• Strong understanding of modern deep learning, especially transformers and embeddings.
• Experience with LLM integrated or knowledge intensive systems.
• Experience designing evaluation frameworks and metrics for ML systems.
• Strong programming skills in Python and at least one of Go, C++, or similar.
• Ability to operate in a fast-moving, product-driven environment with high ownership and autonomy.

Requirements

• Experience with large scale search or recommendation systems.
• Background in agentic AI systems (agents, tool use, autonomous workflows).
• Experience with RAG, multi-step retrieval, or tool use.
• Publications, open source, or similar signals of technical depth and impact.

Benefits

• Competitive compensation.
• Career growth and learning opportunities.
• Flexibility and ownership.
• Collaborative and innovative culture.
• Opportunity to work on impactful AI projects.
• International environment and talented teams.

Company Description

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.

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.