Senior Software Developer: Models Team (Token Factory) in London

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.

About the Product: Token Factory is focused on building a next-generation platform that enables companies to seamlessly integrate AI into their products and workflows. Our vision is to create a powerful, open, and scalable alternative for deploying and managing AI systems—making advanced AI infrastructure more accessible to both fast-growing startups and large enterprises. We work with a wide range of customers, from AI-first companies to established technology organisations, helping them run AI workloads reliably at scale. Our goal is to become a leading platform for high-performance AI inference, delivering predictable latency, strong reliability, and the ability to scale to meet demanding production needs. Customer feedback plays a central role in how we build—our development process is highly iterative and closely aligned with real-world use cases.

About the Team: The Models Team is responsible for onboarding state-of-the-art (SOTA) open-source models into Nebius TokenFactory, including models such as DeepSeek V4 Pro, GLM 5.1, Kimi K2.6, and Minimax M2.7. A major focus of the team is serving large-scale AI models efficiently and reliably in production. To achieve this, we work on advanced inference and systems optimization techniques, including:

• Cache-aware routing
• NUMA-aware deployments
• KV-cache offloading
• Disaggregated serving architectures
• Autoscaling with high-speed model loading over InfiniBand / RoCE

The team maintains and extends forks of leading inference frameworks such as vLLM and TRT-LLM. We have deep expertise in production-scale model serving and regularly support the Solutions Architects team on the most demanding customer PoCs. To operate efficiently at scale, we invest heavily in tooling and automation. Examples include:

• Performance, quality, and smoke-testing frameworks
• Hyperparameter optimization for inference framework configurations
• Gibberish detection systems
• Automated rollout pipelines for inference framework upgrades
• Diagnostics and observability tooling
• Traffic replay systems
• Automated search for optimal serverless deployment configurations

We collaborate closely with model builders, open-source communities, Nebius Cloud teams, and hardware vendors to continuously improve our serving infrastructure. The team is highly goal-oriented and outcome-driven, with a strong focus on delivering results rather than following rigid processes.

Team Structure: We are currently a team of eight engineers distributed across Europe, with members based in the Netherlands, the United Kingdom, Germany, and Latvia. Our workflows are optimized for remote collaboration. At the same time, we meet in person every one to two months at one of our locations to work together, brainstorm new ideas, and plan upcoming milestones. While many team members joined without extensive AI/ML experience, we have rapidly developed strong expertise in large-scale model serving and AI infrastructure.

Technology: Our work is deeply integrated with the broader cloud and infrastructure ecosystem. We primarily use Go and Python to build and scale backend systems. We collaborate closely with teams working on cloud infrastructure, observability, reliability, fault tolerance, and platform engineering. The challenges we solve sit at the intersection of distributed systems, high-performance computing, and modern AI infrastructure.

We expect you to have:

• Experience serving LLMs in production
• Strong Python and/or Go programming skills
• Experience designing and operating highly scalable, highly available distributed services

Nice to have:

• Contributions to vLLM, SGLang, TRT-LLM, or NVIDIA ecosystem open-source projects
• Deep understanding of KV cache management, speculative decoding, and quantization
• Experience with LLM evaluation frameworks
• Hands-on experience with performance benchmarking and optimization
• Deep understanding of Kubernetes
• Familiarity with distributed serving architectures and autoscaling
• Knowledge of InfiniBand, RoCE, or high-performance networking

Benefits & Perks:

• 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

What's it like to work 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.