Principal Backend Software Engineer - Auth & Identity

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 our platform and expand our engineering organisation, we are looking for leaders who can build strong teams, uphold high standards, and deliver reliably at paceWhat You’ll Do:As a Software Engineer at Radiant, you’ll be a hands-on technical leader, driving the design and development of our most critical systems, including our GPU orchestration layer, inference-serving infrastructure, and core platform APIs.You’ll set the standard for engineering excellence across the team, working closely with other principal engineers to align on strategy and drive technical leadership. You’ll partner with peers in infrastructure and machine learning to deliver high-performance AI systems, and mentor engineers across multiple squads. While you won’t have direct reports, you’ll play a pivotal role in shaping engineering direction, design decisions, and cross-team collaboration.Design and build proprietary identity federation, authentication, and authorization infrastructure that securely connects cloud services, customer tenants, and external identity providers (Azure AD, Okta, Google Workspace, etc.) across the Radiant AI cloud platform.Architect and develop native IAM, federation, and role-based access control systems that enable secure interoperability between cloud services, customer tenants, and third-party identity providers.Build foundational identity federation and authorisation technologies beyond cloud-managed integrations.Develop and maintain authentication and authorization services, including OAuth2, OIDC, SAML,