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Core Web Vitals & Performance Audit

We optimize your website for speed, stability, and real-world performance

We help startups and growing companies fix slow loading times, poor Core Web Vitals, and performance bottlenecks. Your product becomes faster, more reliable, and ranks higher in search.

Why Core Web Vitals Matter

Speed = conversions, SEO, and user satisfaction

Google ranks websites based on real user performance, not theoretical metrics. If your app scores poorly on:

LCP (Largest Contentful Paint)
INP (Interaction to Next Paint)
CLS (Cumulative Layout Shift)
TTFB (Time to First Byte)

…you will lose users, SEO visibility, and revenue. We fix these issues using engineering, not shortcuts.

What We Audit & Optimize

Rendering & Architecture

We analyze how your pages render and load:

  • Server-side, static, or client-side rendering issues
  • Next.js App Router / Pages Router mismatches
  • Layout shifts and hydration problems
  • Slow API responses blocking rendering

Performance Metrics

Deep audit of:

  • LCP (images, hero sections, server response)
  • INP (interaction delays, JS blocking, event handlers)
  • CLS (layout shifts from images, fonts, ads, UI components)
  • FID, FCP, SI, TTFB

JavaScript & Bundling

We identify and fix:

  • Large JS bundles
  • Inefficient components
  • Heavy libraries
  • Unnecessary re-renders
  • Missing React memoization
  • Misconfigured Next.js caching

Images & Media Optimization

We optimize:

  • Hero images
  • Unoptimized backgrounds
  • Missing width/height
  • Missing Next.js Image component

Next.js Image alone often improves LCP by 300–600 ms.

Server & API Performance

We debug backend bottlenecks:

  • Slow API routes
  • Overloaded endpoints
  • Missing caching headers
  • Cold starts (serverless)
  • Database latency

Caching & CDN Layers

We configure:

  • Edge caching
  • Static generation
  • Revalidation
  • CDN headers
  • ISR (incremental static regeneration)

Lighthouse & Web Vitals Reporting

You receive:

  • Full Lighthouse reports
  • Before/after comparison
  • Clear explanations — not generic "fix unused JS" text
  • Prioritized list of what to fix first

What You Get (Deliverables)

Complete Performance Report

Including reproduceable testing and detailed recommendations.

Fixes & Implementation

We can implement all improvements directly in your project.

Next.js Optimization

Best practices for:

  • App Router
  • SSR vs SSG vs ISR
  • Edge functions
  • Middleware
  • Bundling strategy

Monitoring Dashboard

We set up dashboards that continuously track:

Metrics:

  • LCP, INP, CLS
  • Errors, crashes
  • Slow API routes
  • JS blocking
  • Real user metrics

Using tools like:

  • Vercel Analytics
  • Google Analytics 4
  • Sentry
  • Logflare / Supabase logs
  • Grafana

Results You Can Expect

Most websites see improvements like:

LCP reduced by 40–70%
CLS dropped to almost zero
INP improved by 150–500 ms
Total bundle size reduced by 20–60%
Page load speed increased 2–5×

And for SEO:

  • Higher Google rankings
  • Higher conversion rates
  • Lower bounce rate
  • Better user retention

Who Is This For?

Startups

You need fast loading for conversions and credibility.

SaaS products

Slow dashboards = lost trial users.

E-commerce & marketplaces

Speed directly affects sales.

Next.js websites

We specialize in performance at framework-level, not only on page-level.

Companies preparing for SEO growth

Performance is the foundation of all ranking.

Example Issues We Commonly Fix

Slow Hero Section

LCP at 3.5–6 seconds → optimized to 1.2–1.8s.

Layout Shifts

CLS 0.25–0.45 → reduced to 0.01–0.04.

Bloated JS

3–7MB JS bundle → reduced to <1.5MB.

Bad API Response Time

800–1500 ms → reduced to 120–300 ms.

FAQ

How long does a performance audit take?

3–10 days depending on project size.

Can you fix the issues after the audit?

Yes — we can implement all improvements.

Do you work with non-Next.js projects?

Yes, but Next.js is our strongest expertise.

Will this improve our SEO?

Yes — Core Web Vitals are a ranking factor.

Startup Engineering Berlin

Full-cycle software development for startups and enterprises

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Core Web Vitals & Performance Audit | Next.js Performance Optimization | Berlin & Germany