Eliminate Forced Layout Reflows

How to optimize koditt.nl

Next.js SiteScore: 75/100Analyzed May 2026Re-analyze this site

Eliminate Forced Layout Reflows

High Impact+12 points estimated

Why It Matters

JavaScript is triggering 389ms of forced reflows, significantly impacting First Input Delay and user interactivity.

How to Fix

Audit the JavaScript chunks causing reflows (0zut2zdu159pe.js and 03dhd84dz2389.js). Batch DOM reads and writes together. Use CSS transforms instead of changing layout properties. Consider using React's Concurrent features to break up long tasks.

0Needs Improvement

What This Score Means

A score of 75 falls in the "Needs Improvement" range (50-89). While it is better than poor (0-49), you should aim for 90+ to provide an optimal user experience and maximize SEO benefits.

This site is slower than approximately 35% of similar sites. The main issues affecting performance are image optimization, JavaScript execution time, and layout stability.

Addressing these issues could improve your conversion rate by 15-20% and boost your search engine rankings.

Core Web Vitals Analysis

LCP

Largest Contentful Paint

3.8s
Needs Improvement

Good: < 2.5s

Measures how long it takes for the main content to appear on screen

INP

Interaction to Next Paint

232ms
Needs Improvement

Good: < 200ms

Measures how quickly the page responds to user interactions

CLS

Cumulative Layout Shift

0.00
Good

Good: < 0.1

Measures visual stability - how much content shifts during page load

AI Performance Analysis

This Next.js site has mediocre performance with a score of 75/100, but several critical issues are holding it back. The biggest problem is excessive unused JavaScript (453 KiB of wasted code) which is causing a slow Time to Interactive of 6.8 seconds and blocking the main thread for 6 seconds. The site is also experiencing forced reflows that create a sluggish First Input Delay of 230ms, making interactions feel unresponsive. Removing unused JavaScript from Google Tag Manager and other scripts, along with fixing the layout thrashing issues, could dramatically improve both loading speed and user interactivity.

Other Optimization Recommendations

Reduce Unused JavaScript Bundle Size

High Impact+15 points estimated

Why It Matters:

Unused JavaScript is consuming 453 KiB and delaying LCP by 600ms while blocking main thread interactions.

How to Fix:

Implement code splitting in your Next.js app using dynamic imports for large components. Use next-bundle-analyzer to identify unused dependencies. Configure tree-shaking properly and consider lazy loading Google Analytics/Tag Manager scripts after user interaction.

Optimize Legacy JavaScript Polyfills

Medium Impact+8 points estimated

Why It Matters:

Modern browser features are being unnecessarily polyfilled, adding 14 KiB of redundant code that slows parsing.

How to Fix:

Update your Next.js browserslist configuration to target modern browsers (>95% support). Remove polyfills for Array.prototype.at, Object.hasOwn, and other Baseline features. Use differential serving to send modern JS to capable browsers.

Keep Your Site Fast After Optimization

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