Software Development Engineer II, App Assembly

Amazon's Store Authoring Foundations team is looking for a passionate, experienced software developer to help build the next generation of mobile shopping experiences on the Amazon Shopping app. You'll work on the server-driven UI framework and mobile runtime that power dynamic experiences for hundreds of millions of shoppers on iOS and Android. Our technology enables thousands of Store builders across Amazon to author, deploy, and iterate on shopping experiences without app updates, combining native performance with the velocity of server-driven rendering. You'll design and build systems that span React Native, native iOS/Android, and backend services, operating at a scale where milliseconds of latency and fractions of a percent in error rates translate to millions of customer interactions. The ideal candidate is passionate about mobile performance, reactive architectures, and building developer platforms that multiply the productivity of other engineers. This person has thrived in delivering high-quality, cross-platform solutions in a fast-paced environment and is energized by the challenge of balancing reliability at massive scale with rapid feature delivery. If you want to work on foundational infrastructure that directly shapes how customers experience Amazon on their phones, and see your impact in real-time metrics serving real shoppers, we'd love to talk to you. Key job responsibilities - Design, develop, and maintain cross-platform mobile infrastructure using React Native, Swift/Objective-C, and Kotlin that serves hundreds of millions of shoppers - Build and optimize server-driven rendering pipelines that enable dynamic UI experiences without requiring app updates - Own the full development lifecycle for features spanning native mobile clients, JavaScript runtime layers, and backend services - Improve performance and reliability of the mobile rendering stack, including bundle loading, data fetching, and rendering prioritization - Collaborate with partner teams to define and evolve bridge APIs, data contracts, and plugin interfaces that thousands of internal builders depend on - Instrument, monitor, and respond to production metrics, driving down latency and error rates through data-driven iteration - Participate in on-call rotations and operational excellence practices for tier-1 mobile infrastructure - Mentor junior engineers through code reviews, design discussions, and technical guidance - Contribute to technical roadmap planning, identifying opportunities to reduce complexity, eliminate tech debt, and improve developer experience for internal customers A day in the life This role is AI-native. You are expected to use AI tooling daily to accelerate development, code review, and problem-solving. Day to day, you'll write and review code across React Native, native iOS/Android, and backend services. You'll collaborate with Store builder teams who depend on your platform to ship shopping experiences to hundreds of millions of customers. You'll investigate production issues, optimize rendering performance, design cross-platform APIs, and balance shipping new capabilities with maintaining reliability at scale.

The App Assembly team owns the native and JavaScript runtime that assembles and renders server-driven shopping experiences on iOS and Android. We fetch blueprints, parse layout trees, resolve data reactively through our unified data layer, and render interactive UI via React Native. Our systems serve hundreds of millions of shoppers and enable experience teams across Amazon to ship without app updates. We're a small, high-ownership team where engineers work across Swift, Kotlin, and TypeScript daily. We value cross-platform craftsmanship, performance rigor, and building reliable foundations others depend on. Based in Seattle.