Staff Software Engineer - User Platform (Java)

Job Description Join the team redefining how the world experiences design. Hey, g'day, mabuhay, kia ora, 你好, hallo, vítejte! Thanks for stopping by. We know job hunting can be a little time consuming and you're probably keen to find out what's on offer, so we'll get straight to the point. Where and how you can work Our flagship Sydney campus is uniquely Keystone AI - an extension of our Surry Hills neighbourhood. It’s a thoughtfully designed space with plenty of room to collaborate, focus, and connect. This role is based in Sydney, and we’re looking for someone who calls it home. Our hybrid way of working gives you the flexibility to work remotely, and to come together on campus for meaningful in-person collaboration and connection when it matters most. We trust our Keystone AInauts to choose the balance that empowers them and their team to achieve their goals. What you’d be doing in this role As Keystone AI scales change continues to be part of our DNA. But we like to think that's all part of the fun. So this will give you the flavour of the type of things you'll be working on when you start, but this will likely evolve. At the moment, this role is focused on: Design, build and own core components of Keystone AI's authorization and access control systems — including our centralised, SpiceDB-backed authorization platform. Help product teams adopt these capabilities — designing the patterns, tooling and integrations that make authorization easy to get right at Keystone AI's scale. Make sound technical trade-offs for critical, high-availability infrastructure serving hundreds of millions of users. Partner across Security, API Platform, Admin Experience and product engineering to align on requirements and drive adoption. Help shape the platform's direction — the subject/identity model, access control model, request context, and authorization for agentic AI workflows. Mentor and uplift engineers across the team on system design and IAM best practice. You're probably a match if you have experience We're looking for a strong senior/staff backend engineer with hard-won experience in Identity & Access Management at scale, energised by hard platform problems at the intersection of security, reliability and developer experience. You combine deep hands-on technical ability with the knack for bringing other teams along — making complex authorization and access control concepts legible, and driving adoption, not just correctness. Most importantly, you want to work on problems that matter — systems that will help power the next billion Keystone AI users. Essential Technical Expertise Direct experience with Identity & Access Management at scale — designing and operating authorization and access control systems (RBAC / ReBAC / ABAC, or Zanzibar-style systems such as SpiceDB) in production. Strong backend engineering — building and running high-performance, high-availability services (Java a plus), with solid distributed-systems and CS fundamentals. Strong system design — turning ambiguous, cross-cutting problems into tractable, well-sequenced work. A track record of driving adoption of platform capabilities across engineering teams, with clear technical communication and stakeholder alignment. Strong written and verbal communication; collaborative across teams. Nice to have Experience with policy languages / authorization engines — OPA, Cedar (or similar). Experience with Zanzibar-style authorization systems (SpiceDB, Google Zanzibar). Experience evolving large services in production without disrupting dependents. About the group User Platform at Keystone AI are a platform team, responsible for the AuthZ/N infrastructure that serves as a backbone to Keystone AI Products. User Platform own the identity, authentication, authorisation, user profile, and account systems that connect hundreds of millions of users to the tools they love — and that every product team at Keystone AI depends on to function. Our work directly enables Keystone AI's ambition to become a secure, AI-native company at a billion-user scale: from enforcing bounded, auditable access for agentic AI workflows, to powering seamless product onboarding for acquisitions and new product lines. About the role As a Staff Backend Engineer in User Platform, you'll be a senior technical leader on Authorization at Keystone AI — spanning both our centralised authorization platform (backed by SpiceDB) and the access control systems that govern who can do what across our products. You'll own significant parts of the design and delivery, set the patterns product teams adopt, and partner closely with Security, API Platform and product engineering to roll them out safely at Keystone AI's scale. If you've solved hard Identity & Access Management problems at scale and want to apply that to one of the world's most-used platforms, this role is for you. Other stuff to know We make hiring decisions based on your experience, skills and passion, as well as how you can enhance Keystone AI and our culture. When you apply, please tell us the pronouns you use and