Senior Software Engineer (Agentic Search) - Web Access Engineer

About the Position

Join Nebius as a Senior Software Engineer to enhance web access infrastructure for AI systems, focusing on reliability and efficiency.

About the Company

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.

The Role

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

In this role, you will focus on making our access to public web content reliable and efficient. You will investigate how modern websites and browsers communicate across the full request lifecycle, find the root cause when a request fails or returns something unexpected, and build the fixes into production systems operating at internet scale. Your work ensures that high-quality content is consistently available to the crawling, indexing and retrieval systems downstream.

Responsibilities

• Diagnose failed or degraded requests at the right layer: network and IP, TLS and HTTP/2 behavior, headers and session state, client-side scripts, or browser characteristics
• Analyze how websites verify and classify clients, including how client-side scripts and protocol-level behavior shape what a site serves to different clients
• Build clients and tooling that behave consistently and compatibly with standard browsers across all of these layers, using a real browser where a lightweight client is not enough
• Monitor access quality as websites change: detect regressions, find the cause, and measure success on real content rather than on status codes
• Build the tooling to do this at scale: traffic capture and comparison against real browsers, per-site and per-method success tracking, and the cost of each successful fetch
• Choose the fetch method for each host, from a lightweight HTTP client to a full browser, balancing quality against cost

Requirements

• Have 5+ years of experience building production systems, and are an expert in several of the following areas:
  • HTTP/1.1, HTTP/2 and HTTP/3, TLS handshakes and TLS fingerprints (JA3/JA4), and header behavior
  • What a server can observe at each step of a request, and what a client controls at each step
  • A debugging method, not guesses: replaying captured browser traffic, comparing against a real browser on the same network path, and changing one variable at a time
  • Reading and analyzing complex or obfuscated JavaScript, and observing what a script measures by hooking browser APIs
  • How browser, device and network characteristics are measured (canvas, fonts, WebGL, screen and window metrics) and how consistent they are across layers
  • Browser instrumentation and the Chrome DevTools Protocol, used as tools for investigation
  • Strong programming in at least one of Go, Python, Rust or C++

Nice to Have

• Working at a web data provider, a browser or web-security company, or a company that collects data from complex sources
• Contributions to browser networking or fingerprinting-related open-source tooling, or public write-ups of how client verification works
• Building or maintaining a patched browser
• Networks, proxies and IP reputation
• Internet-scale distributed systems, Kubernetes and cloud infrastructure

We Offer

• 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

About Working at Nebius

Fast moving - Bold thinking - Constant growth - Meaningful impact - Trust and real ownership - Opportunity to shape the future of AI

Equal Opportunity Statement

Nebius is an equal opportunity employer. We are committed to fostering an inclusive and diverse workplace and to providing equal employment opportunities in all aspects of employment. We do not discriminate on the basis of race, color, religion, sex (including pregnancy), national origin, ancestry, age, disability, genetic information, marital status, veteran status, sexual orientation, gender identity or expression, or any other characteristic protected by applicable law.

Applicants must be authorized to work in the country in which they apply and will be required to provide proof of employment eligibility as a condition of hire.

If you need accommodations during the application process, please let us know.

Locations

• Amsterdam, Netherlands
• Israel
• London, United Kingdom