Senior Frontend Performance Engineer - React.js/Javascript

<p>About The Role<br/><br/>We are seeking a dedicated Senior Frontend Performance Engineer to focus entirely on optimizing the speed, responsiveness, and Core Web Vitals of our user-facing applications.<br/><br/> You will be responsible for defining and driving our performance budget, architecting solutions for faster load times, and ensuring a world-class user experience across all devices.<br/><br/>Key Responsibilities<br/><br/>Performance Strategy : </p><p><br/></p><p>- Establish and maintain clear performance budgets (i.e., Largest Contentful Paint - LCP, First Input Delay - FID, Cumulative Layout Shift - CLS) and best practices across the engineering organization.<br/><br/>- Instrumentation & Analysis: Implement, configure, and manage Real User Monitoring (RUM) and synthetic monitoring tools.<br/><br/>- Analyze performance data to identify critical bottlenecks in JavaScript, CSS, and asset loading.<br/><br/>Optimization : </p><p><br/></p><p>- Lead initiatives for critical rendering path optimization, code splitting, dynamic imports, image/media optimization, and advanced caching strategies (Service Workers, CDN).<br/><br/>Architecture : </p><p><br/></p><p>- Collaborate with Architects and Product teams to review design decisions and ensure new features are performant by default (i.e., efficient data fetching, state management).<br/><br/>CI/CD Integration : </p><p><br/></p><p>- Integrate automated performance testing and regression analysis into our Continuous Integration (CI) process.<br/><br/>Technical Skills (Must-Have) : </p><p><br/></p><p>- Web Fundamentals: Expert knowledge of core web technologies (HTML, CSS, JavaScript) and browser rendering processes.<br/><br/>Framework Experience : </p><p><br/></p><p>- Deep experience with a modern JavaScript framework like React, Next.js, or Vue.s, with a focus on optimization techniques specific to that framework.<br/><br/>Performance Tools : </p><p><br/></p><p>- Expert proficiency with profiling tools (Chrome DevTools, WebPageTest, Lighthouse) and monitoring solutions (Datadog RUM, New Relic, or self-hosted RUM).<br/><br/>Bundlers & Tooling : </p><p><br/></p><p>- Strong experience configuring and optimizing build tools (Webpack, Rollup, Vite).<br/><br/>Advanced JS : </p><p><br/></p><p>- Practical knowledge of advanced JavaScript concepts (event loop, memory management, asynchronous patterns) and how they impact performance.<br/><br/>CI/CD & Git : </p><p><br/></p><p>- Experience integrating performance checks into a modern CI/CD pipeline.<br/><br/>Qualifications : </p><p><br/></p><p>- Bachelor's degree in Computer Science, Engineering, or a related technical field.<br/><br/>- 5+ years of professional experience in frontend development, with at least 3 years dedicated to large-scale performance optimization initiatives.<br/><br/>- A strong portfolio or history of work that demonstrates quantifiable improvements in web performance metrics<br/></p> (ref:hirist.tech)