Frontend Engineer II, IES Latency

About Us

The IES Latency team owns Lightsaber a progressive and proximal rendering framework that makes Amazon pages load faster by serving content locally from the customers device while fetching dynamic content from the server in parallel.
Lightsaber has made Android mShop faster than iOS on key shopping pages a result that defies conventional expectations and demonstrates the power of software-driven latency optimization over hardware advantages. We operate across the
full stack from Service Workers running in the browser to backend services behind Shopping Portal optimizing latency for hundreds of millions of shoppers on mShop (Android & iOS) mobile web and desktop across all Amazon marketplaces
2026 our focus is bringing these same capabilities to iOS to close the gap while continuing to push Android latency even lower.

Key job responsibilities
Technical Areas

- mShop Android app: Service Workers Cache Storage API page shell caching prefetching skeleton loaders rendering hints TRIMs transitions
- mShop iOS app: Rendering hints skeleton experiences deeplink latency optimization via JumpStart
- Client-side performance: TypeScript streaming response composition browser rendering pipeline perceived latency techniques
- Backend services: Java Spring Horizonte ECS Fargate NLB BigMesh Shopping Portal integration
- Experimentation: Weblab design triggering strategies latency metric analysis business impact measurement across 20 marketplaces
- Operational excellence: Owning and operating two Tier-1 services (Lightsaber and AUIServiceWorkerService) CloudWatch RTLA CI/CD pipelines chaos testing autoscaling cross-AZ load balancing Zonal Shift

A day in the life
What Youll Work On

- Lightsabers core client engine page shell caching prefetching skeleton loaders and rendering hints that reduce page load times by 50-120ms on core shopping pages (Detail Page Search Checkout Homepage Cart)
- TRIMs (Trust Reinforcing Microinteractions) perceived latency experiences using motion and visual feedback during page transitions to improve checkout conversion
- Launching Lightsaber on iOS mShop bringing rendering hints and skeleton experiences to iOS closing the latency gap where iOS DP latency (1071ms) significantly lags Android (815ms)
- AUIServiceWorkerService a Horizonte/Spring backend service running on ECS behind Shopping Portal that serves service worker scripts and CSRF tokens to millions of concurrent users
- Collaborating with partner teams across Shopping Portal Detail Page Search Checkout Cart Homepage Mobile Shopping Foundations and AUI to design experiment and launch latency optimizations across the shopping funnel

Impact

- Your work directly reduces page load times for 500M shoppers across every Amazon marketplace
- TRIMs targets $40MM OPS and $80MM cumulative CSales through improved perceived performance
- Youll own the full lifecycle from design and experimentation to production launch and operational health of Tier-1 services

- 2 years of non-internship professional front end web or mobile software development using JavaScript HTML and CSS experience
- 1 years of computer science fundamentals (object-oriented design data structures algorithm design problem solving and complexity analysis) experience
- Experience using JavaScript frameworks such as angular and react

- 1 years of agile software development methodology experience
- Experience with common front-end technologies such as HTML CSS JS TypeScript and Node

Our inclusive culture empowers Amazonians to deliver the best results for our customers. If you have a disability and need a workplace accommodation or adjustment during the application and hiring process including support for the interview or onboarding process please visit for more information. If the country/region youre applying in isnt listed please contact your Recruiting Partner.