Principal Software Engineer - Storage

What You'll Do As a Principal Software Engineer - Storage, you will help set the technical direction for Radiant's cloud storage offering and lead the design and delivery of the storage services and data capabilities required to run demanding cloud and AI workloads at scale. You'll work across object, block, and file storage, data lifecycle, performance, resilience, APIs, and platform integrations. You'll partner closely with product, infrastructure, SRE, networking, and security teams, and with customers running the most demanding storage workloads. This is a hands-on technical leadership role focused on building storage services that are high-performance, reliable, scalable, and easy to consume, through architecture, code, and the standards other teams build on. Key Responsibilities Set the technical vision and architecture for Radiant's storage services, and lead their design and implementation. Design and build storage systems across object, block, and file, including the control plane, the data plane, and integration with existing Radiant services. Translate product and customer requirements into robust architectures, APIs, and technical designs, working closely with the Storage Product Manager. Own the performance, durability, availability, and consistency characteristics of the storage platform, and define the service levels it can credibly meet. Profile, benchmark, and tune throughput, latency, and IOPS for AI training, inference, and other data-intensive workloads. Lead integration of storage with compute, Kubernetes (CSI), networking, IAM, observability, and developer tooling. Design for failure through replication, snapshots, data protection, failure recovery, and safe upgrades at scale. Drive operational excellence with SRE, including capacity planning, observability, incident response, and post-incident improvements. Raise the engineering bar across the organisation through mentoring, design and code review, and technical standards. Your Profile Extensive experience building and operating large-scale distributed storage systems or storage-heavy cloud infrastructure. A track record of technical leadership at staff or principal level, including setting direction across multiple teams and delivering complex, high-stakes systems. Strong hands-on engineering skills in one or more systems languages such as Go or similar. Deep technical expertise across: Storage: object, block, and file storage, snapshots, replication, erasure coding, caching, tiering, data lifecycle Protocols & interfaces: S3, NFS, SMB, CSI, NVMe/NVMe-oF, RDMA, POSIX semantics, storage APIs Infrastructure: Kubernetes, containers, high-performance networking, GPU clusters, cloud platforms Reliability: durability, availability, consistency models, consensus, failure recovery, data integrity Observability & security: metrics, logging, tracing, IAM, encryption at rest and in transit, auditability Hands-on experience with technologies such as WEKA, VAST, DDN, Lustre, Ceph, MinIO, Pure Storage, or similar. Understanding of AI and HPC storage patterns, such as large-scale training data pipelines, checkpointing, and high-throughput parallel file systems. Able to reason about trade-offs between performance, durability, availability, cost, and operational complexity. Excellent written and verbal communication, including clear design documents and explaining complex trade-offs to technical and non-technical audiences. Comfortable working directly with customers on highly technical problems. What You Bring Storage domain expertise: Understand how storage architecture affects application and workload performance, down to the hardware. Engineering excellence: Write and review code that sets the standard for correctness, performance, and maintainability. Architectural judgement: Make sound long-term decisions on systems where data loss is not an option. Technical leadership: Influence direction across teams without relying on authority, and grow the engineers around you. Systems thinking: Understand how storage interacts with compute, networking, and the rest of the cloud platform. Ownership: Drive storage capabilities from design through production, operation, and continuous improvement. Qualities we look for: Set the standard: Every single day, you spot opportunities to constructively shake things up Inspire the change: There's no blueprint for the future. You'll embrace challenges and change You're real and you're true to yourself: We cherish and celebrate diversity so you'll feel right at home whoever you are and whoever you're talking to, you treat everyone the same. Why should you join us? What sets us apart is our blend of modern technology, competitive benefits, and an open, welcoming work culture that enables our people to thrive. Here are just some of the great things you can expect from us: 25 days of annual leave A culture that emphasises results over hierarchy, process & ego: we place great emphasis on the quality, ingenuity and creativity of work. Open communication, regular feedback: we value smooth collaboration, direct and actionable feedback, and believe that leading with empathy and a growth mindset makes us better together. Learning Time: we all have dedicated learning time to focus on new skills, projects or interests that lay outside of your day-to-day job. Health & Wellbeing: we want everyone to feel healthy and happy, so we offer private medical insurance via Bupa. Cycle to Work Scheme: we're committed to building a sustainable business, so we encourage cycling to work. Gympass subscription to a variety of gyms and wellbeing apps Participation in the company shares program Enhanced parental pay & leave Our process: Talent screen → Hiring Manager → Technical interview (two Principal Engineers) → Whiteboard Session → Final. Company Overview: Radiant is redefining how AI infrastructure is built. We design and operate AI-native cloud platforms engineered for sovereignty, performance, and scale. Our infrastructure powers GPU-native workloads, multi-tenant control planes, and high-performance AI systems designed for the most demanding environments. We are not building a generic cloud. We are building purpose-built AI infrastructure — from powered land, to compute, to software. As we scale, we're building this organisation from the ground up. We're looking for people who'd rather build the playbook than inherit one — who are comfortable doing the work themselves as well as directing others, and who can adapt as fast as our strategy does. This is a startup model: attitude and adaptability matter more to us than years of experience or the size of the team you've previously managed.