Staff / Senior Software Engineer (Agentic Search) - Runtime

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 Product

In a rapidly evolving world, trust in AI depends on AI agents being grounded in fresh, verified real-world data. Search is the foundation that makes this possible.

We are building an agent-native search platform designed specifically for AI systems rather than human users. Our product provides programmatic, low-latency, and observable search APIs that AI agents use to retrieve, filter, and reason over real-world information at scale.

The Role

We are looking for a Senior Software Engineer to work on the runtime systems of a novel search engine tailored for agentic AI consumption.

In this role, you will focus on building low-latency, high-throughput systems that serve search queries in real time. You will work on the critical path of user-facing requests, where performance, predictability, and efficiency directly impact product quality. You will design and operate systems that handle thousands of requests per second under strict latency budgets, optimising every layer from request handling to data access and response assembly.

In this position, your responsibility will be to

Design, implement, and operate core runtime services for serving search queries at scale

Build and optimise request flows, including query processing, retrieval orchestration, and response assembly under strict latency budgets

Develop systems that maintain performance and predictability under high load

Optimise CPU, memory, and data access patterns in performance-critical paths

Ensure reliability, observability, and predictability across production services

Build well-tested systems with clear responsibilities and interaction contracts, while remaining flexible as architecture evolves

Define and implement observability primitives, including structured logs, metrics, traces, and latency breakdowns

Monitor throughput, latency, and resource usage, and drive improvements in performance and cost efficiency

Collaborate with indexing and ML teams to integrate retrieval and ranking components, keeping ML logic decoupled from core system internals

Support experimentation and iteration through controlled rollouts and rigorous benchmarking

You may be a good fit if you:

Have 5+ years of experience as a software engineer working on production backend systems

Have strong hands-on expertise in C++ or Rust in real-world, high-load services

Have built and operated high-load, low-latency user-facing systems handling thousands of RPS under strict latency constraints

Understand performance at a systems level — CPU, memory, networking, and data access

Have operated your own code in production: deployed it, debugged incidents, and rolled back changes when necessary

Think end-to-end about request flows rather than staying within isolated components

Can balance correctness, latency, and development velocity, making pragmatic tradeoffs when scope or time requires

Collaborate effectively across engineering, ML, and product teams, communicating clearly in cross-functional settings

Strong candidates may also have experience with:

DBMS internals (open source or SaaS) and cloud infrastructure

High-load web applications or large-scale APIs

Performance-critical systems …