Fix Render Blocking CSS

How to optimize pwa.opusapp.eu

Generic SiteScore: 73/100Analyzed April 2026Re-analyze this site

Fix Render Blocking CSS

High Impact+12 points estimated

Why It Matters

Critical CSS blocks initial render and delays LCP by 450ms, preventing users from seeing content quickly.

How to Fix

Extract critical above-the-fold CSS and inline it in the HTML head. Load the remaining CSS asynchronously using media='print' onload='this.media="all"' technique. Remove 87% of unused CSS rules from your main stylesheet to reduce bundle size from 24KB.

0Needs Improvement

What This Score Means

A score of 73 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

4.3s
Poor

Good: < 2.5s

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

INP

Interaction to Next Paint

16ms
Good

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 web application has moderate performance issues with a score of 73/100, but users are experiencing frustratingly slow loading times. The biggest problem is excessive unused JavaScript code, which is wasting 441 KB and delaying both First Contentful Paint (4.2s) and Largest Contentful Paint (4.3s) by over 2 seconds. The site is loading nearly three times more JavaScript than it actually uses, with the main application file being 91% unused code. Removing or deferring this unused JavaScript, along with addressing render-blocking CSS issues, could dramatically improve loading speed and push the performance score well into the green zone.

Other Optimization Recommendations

Eliminate Unused JavaScript Code

High Impact+18 points estimated

Why It Matters:

Unused JavaScript wastes 441 KiB and delays LCP by 2.25 seconds, significantly impacting user experience.

How to Fix:

Implement code splitting using dynamic imports for your main bundle (253KB unused). Move chart library to lazy-load only when needed. Use tree-shaking to remove dead code from Sentry bundle. Consider switching to a lighter error tracking solution if full Sentry features aren't needed.

Optimize Sentry Integration Performance

Medium Impact+8 points estimated

Why It Matters:

Sentry library causes 29ms of forced reflows, blocking the main thread and degrading user interactions.

How to Fix:

Move Sentry initialization to after page load using requestIdleCallback. Reduce sampling rate in production to minimize performance overhead. Consider lazy-loading Sentry only when errors occur or use a lighter error tracking solution.

Keep Your Site Fast After Optimization

Once your site is optimized, maintain that speed. Use DeployHQ for zero-downtime, automated deployments—so performance fixes and updates go live safely every time, without breaking your site.

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