You will get Improve Your Web App Core Web Vitals — LCP, CLS, INP & Bundle Size
Project details
Is your app slow to load? Failing Core Web Vitals? Losing users before the first interaction?
I diagnose and fix frontend performance at the bundle, render, and network layers —
with measurable Lighthouse and PageSpeed improvements you can show your team.
I target:
✦ LCP (Largest Contentful Paint) — critical resource prioritization, image optimization
✦ CLS (Cumulative Layout Shift) — skeleton screens, dimension reservations
✦ INP (Interaction to Next Paint) — long task splitting, debouncing, scheduler API
✦ Bundle size — code splitting, lazy loading, tree shaking, dead code elimination
✦ Time to First Byte — SSR/SSG opportunities, CDN configuration advice
✦ Font loading — font-display, preload hints, subsetting
✦ Third-party script impact — async loading, facades, partytown
Tools I use:
→ Lighthouse CI, WebPageTest, Chrome DevTools Performance tab
→ Webpack Bundle Analyzer / Vite Rollup Analyzer
→ React DevTools Profiler
Every engagement ends with a before/after report with real numbers.
I diagnose and fix frontend performance at the bundle, render, and network layers —
with measurable Lighthouse and PageSpeed improvements you can show your team.
I target:
✦ LCP (Largest Contentful Paint) — critical resource prioritization, image optimization
✦ CLS (Cumulative Layout Shift) — skeleton screens, dimension reservations
✦ INP (Interaction to Next Paint) — long task splitting, debouncing, scheduler API
✦ Bundle size — code splitting, lazy loading, tree shaking, dead code elimination
✦ Time to First Byte — SSR/SSG opportunities, CDN configuration advice
✦ Font loading — font-display, preload hints, subsetting
✦ Third-party script impact — async loading, facades, partytown
Tools I use:
→ Lighthouse CI, WebPageTest, Chrome DevTools Performance tab
→ Webpack Bundle Analyzer / Vite Rollup Analyzer
→ React DevTools Profiler
Every engagement ends with a before/after report with real numbers.
Programming Languages
HTML & CSS, JavaScript, TypeScriptCoding Expertise
Performance OptimizationWhat's included
| Service Tiers |
Starter
$150
|
Standard
$300
|
Advanced
$550
|
|---|---|---|---|
| Delivery Time | 1 day | 5 days | 8 days |
Number of Revisions | 1 | 2 | 3 |
Bug Investigation | |||
Fix Documentation | |||
Detailed Code Comments | - |
Optional add-ons
You can add these on the next page.
Lighthouse CI GitHub Actions integration
(+ 3 Days)
+$70Frequently asked questions
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WS
Wassim S.
Jul 4, 2026
fix a bug in my web site
Great experience working with Marwen. He delivered fast, communicated clearly throughout, and kept me updated at every step. Quick to understand what I needed and easy to work with would definitely hire again
About Marwen
Senior Full Stack React Node.js Three.js React Native
Lisbon, Portugal - 4:08 am local time
Web · Mobile · 3D · Performance · Security
Freelance, B2B & contract — DM or email to get started.
Steps for completing your project
After purchasing the project, send requirements so Marwen can start the project.
Delivery time starts when Marwen receives requirements from you.
Marwen works on your project following the steps below.
Revisions may occur after the delivery date.
Environment Setup & Codebase Analysis
Secure access is established, and I audit the repository to pinpoint your exact performance bottlenecks and bundle bloat.
Performance Implementation
I apply targeted optimizations to your codebase, focusing directly on fixing LCP, CLS, INP, and reducing your overall bundle size.