Staff / Principal Applied AI Researcher (Agentic Search)

Nebius B.V.; Amsterdam; On-site; EUR 140,000 - 190,000; Full time

Job summary

Nebius B.V. is seeking a Staff or Principal Applied AI Researcher to advance an agent native search platform in Amsterdam. You will own retrieval architectures, improve grounding of LLMs, and push production-ready AI systems with low latency.

You will design multi-stage retrieval, collaborate with engineers, and mentor team members while targeting measurable impact and scalable AI tooling.

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.

Responsibilities

• Drive applied research and technical direction across retrieval and ranking systems.
• Design and evolve multi stage retrieval architectures (query understanding, rewriting, reranking, iterative retrieval).
• Develop methods for grounding LLMs in real time web data at scale.
• Define and implement new evaluation paradigms and metrics for agentic systems, where correctness is not reducible to clicks.
• Lead experimentation on modern retrieval approaches (embeddings, hybrid search, reranking) and bring them into production.
• Analyse trade-offs across relevance, latency, and cost at scale.
• Work closely with engineering to deploy systems in high throughput, low latency environments.
• Own ambiguous problems end to end and contribute to product and research direction.
• Mentor engineers and help raise the technical bar of the team.

Skills

Applied AI

ML systems

Search systems

Transformers

Embeddings

Python

Go/C++

Tools

Python

Go

C++

Job description

We are 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. You can think of this as Google for AI agents: a system designed for machines, not humans. We are building agentic search, where AI systems actively plan, retrieve, evaluate, and refine information rather than simply returning results. As AI becomes the primary interface to the web, this layer will replace the role of traditional search engines. We are designing how AI agents - not humans - retrieve, evaluate, and reason over web data in real time, under strict latency and reliability constraints. This means solving retrieval and ranking under entirely new access patterns and at significant scale, with systems operating over constantly changing, unstructured data and serving tens of thousands of production workloads 24 by 7. This role comes with ownership over key parts of our applied AI research direction and system design, with a strong expectation of defining new approaches and shipping measurable impact in production.

What you'll work on:

• Designing agent native retrieval systems optimised 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 responsibilites:

• Drive applied research and technical direction across retrieval and ranking systems
• Design and evolve multi stage retrieval architectures (query understanding, rewriting, reranking, iterative retrieval)
• Develop methods for grounding LLMs in real time web data at scale
• Define and implement new evaluation paradigms and metrics for agentic systems, where correctness is not reducible to clicks
• Lead experimentation on modern retrieval approaches (embeddings, hybrid search, reranking) and bring them into production
• Analyse trade-offs across relevance, latency, and cost at scale
• Work closely with engineering to deploy systems in high throughput, low latency environments
• Own ambiguous problems end to end and contribute to product and research direction
• Mentor engineers and help raise the technical bar of the team

Must haves:

• 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

Nice to haves:

• 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

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