Senior Software Engineer (Data Platform, C++)

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 role #LI-MM1 We’re looking for a Software Engineer with strong C++ expertise to join the team building and operating Nebius Data Platform — a distributed storage and a processing platform that acts as the company’s “source of truth” and the backbone of many internal (and some external) products. Nebius Data Platform is a single multi-tenant ecosystem based on YTsaurus — instead of running separate HDFS/Kafka/HBase-style systems, we provide storage, compute, and analytics capabilities inside one platform. Built on top of the open-source YTsaurus ecosystem, we run and extend our own Nebius distribution and develop significant in-house functionality (core and platform-level). We can design, implement, and roll out features end-to-end on our clusters without waiting for upstream approvals and contribute upstream when it makes sense. At scale today, this includes ~500 servers, ~20k CPU cores and ~10 PB of compressed data in our largest production cluster, supporting workloads ranging from business-critical pipelines and financial transactions to large-scale ML/LLM training datasets and compute. What’s inside the platform You’ll work on a system that includes (and ties together): • Distributed Storage (Cypress) : transactional semantics, tiered storage, erasure coding, replication, and strong reliability expectations. • Compute & ETL : a cluster-wide job scheduler (tens of thousands of cores), MapReduce, YQL for SQL-like data processing, and SPYT (Spark over YTsaurus) for modern data engineering. • Interactive analytics (CHYT) : ClickHouse® instances spun up directly on compute nodes for fast SQL over data in-place. • Dynamic Tables : low-latency NoSQL KV with distributed ACID transactions for OLTP-style workloads and feature stores. • Orchestracto : workflow orchestration deeply integrated with the platform (Airflow-like, but platform-native). What you’ll do We’re looking for engineers who combine strong systems skills with product sense : understanding who uses the platform, why certain capabilities matter, and making pragmatic trade-offs to maximize impact. On our team, engineering work is expected to be connected to real users and outcomes — you’ll regularly align with internal stakeholders, clarify requirements, and help drive prioritization. In this role, you will: • Design and implement new functionality in YTsaurus core (C++) with production reliability in mind. • Build and evolve platform-level capabilities: platform architecture and operating model—multi-cluster growth, shared primitives, and a consistent experience that scales with new teams and use cases. • Improve end-to-end platform experience for internal (and external-facing) users: APIs, guardrails, debugging workflows, and automation. • Own production quality: incident response / on-call rotation , root cause analysis, and turning learnings into durable fixes. Example projects • Roll out sharded YTsaurus masters (incl. Kubernetes operator support) and build automatic balancing of metadata across master