Alex Rivera
Senior Frontend Engineer
Austin, TXalex.rivera@email.com(555) 011-3492linkedin.com/in/alexrivera-fealexrivera.dev
Professional Summary
Senior Frontend Engineer with 6 years shipping React/TypeScript at product-led companies. Owned the design system used by 4 teams; lifted Core Web Vitals (LCP 4.2s → 1.8s) on the flagship surface in 90 days. WCAG 2.2 AA fluent.
Experience
Senior Frontend Engineer
Mar 2023 — Present
Helix Health · Austin, TX
- Built a reusable design-system library of 42 accessible React components (WCAG 2.2 AA), adopted across 4 product teams and replacing 11K lines of duplicated UI code.
- Led the rollout of Core Web Vitals tracking and a perf budget in CI, blocking 14 regressions before merge and lifting CrUX LCP from 4.2s to 1.8s in 90 days.
- Shipped a virtualized data table handling 50K+ rows at 60fps, replacing a legacy grid that was the #1 source of customer-support tickets that quarter.
Frontend Engineer
Jun 2020 — Feb 2023
Tessellate · Remote
- Migrated a 60K-line React codebase from JavaScript to TypeScript over two quarters, reducing runtime type errors caught in production by 71% based on Sentry incident counts.
- Reduced initial JS bundle from 2.1MB to 480KB by route-splitting and lazy-loading non-critical components, cutting Largest Contentful Paint by 38% on 3G connections.
- Owned the checkout funnel; A/B test of redesigned validation flow lifted purchase conversion 4.1% (rolled out to 100% of traffic; ~$2.8M annualized GMV impact).
Education
Skills
React · TypeScript · Next.js · Tailwind CSS · Redux · React Query · Jest · React Testing Library · Accessibility (WCAG 2.2) · Performance Optimization · Design Systems · Vite · GraphQL · Responsive Design