Software Development Engineer II, Unified Auth SDK

UnifiedAuth is the authentication and authorization backbone for Amazon's service ecosystem. We secure service-to-service communication, ensuring that every call between Amazon services is authenticated and authorized against the right identity and policy. As Amazon's systems evolve toward autonomous agents, we provide agentic authentication and authorization — establishing verifiable identity and scoped, policy-governed access for AI agents acting on behalf of users and services. We also own transaction token management, issuing, propagating, and validating the tokens that carry identity and authorization context across multi-hop request chains. Together, these capabilities let Amazon's services trust who is calling them, what those callers are permitted to do, and on whose behalf they act — protecting customer data and maintaining the integrity of every transaction across the fleet. We are looking for a Software Development Engineer II to design, build, and operate components of our authentication SDKs and supporting services. You will own features end-to-end: design through production operations across Java, Python, NodeJS, and Rust client libraries. You will collaborate with security teams, service owners, and business teams to close authentication gaps at scale. This role suits an engineer who wants to own ambiguous, high-impact problems in a domain where correctness and availability are non-negotiable. Key job responsibilities - Design and deliver features across Security SDKs, owning them from design document through production launch. - Improve the static stability of authentication — ensure services continue operating through service outages via persistent caching, eager token refresh, and bounce-safe recovery. - Build and maintain telemetry and compliance mechanisms that measure token propagation and detect gaps across the fleet. - Diagnose and resolve production issues as part of the on-call rotation, and drive root-cause analysis and corrections for operational events. - Own pipeline and release health for SDK components — keep pipelines fresh, unblock releases, and reduce time-to-deploy. - Write clear design documents and participate in Operational Readiness Reviews (ORRs) and security reviews. - Mentor SDE1s and interns; raise the technical bar through code reviews and design feedback.