and responsive design) • Localization & Internationalization (Handling multiple locales, date/number formatting, plurals, RTL support, and dynamic language switching) • Component Architecture & Rendering Framework (Design systems, reusable UI components, framework- speci fi c patterns (e.g., React, Vue, etc.)) • State Management (Local/global state, lazy loading, prefetching, and hydration strategies) • Async Flow Management (Fetching, error handling, retries, caching, and suspense-like patterns) • Rendering Performance (Virtual DOM ef fi ciency, avoiding unnecessary re-renders, memoization, prioritizing TTI, and improving LCP). • SSR / SSG Expertise (Familiarity with server-side rendering and static site generation) • Animations & Transitions (Motion design for UX, accessibility-aware transitions, and performance-safe animations) • Front-end Security (XSS prevention, safe DOM manipulations, CSP usage, and secure cookie handling) • Testing & Validation (E2E testing (Playwright, Cypress), visual regression testing, and test coverage for UI behavior) • Build Pipeline & Tooling (Linting, dependency management, tree-shaking, and bundle size optimization (e.g., via Vite, Webpack)) • Analytics & Instrumentation (Event tracking, tagging plans, performance monitoring, cookie consent, and GDPR- compliant data collection)