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https://cbs.nl

Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
86
GRADE
B
FIX
2
REVIEW
3
PASS
8
INFO
2

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
86
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
92
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
100
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
92
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

990 ms

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

1.53 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

0 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.158

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

1.02 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

1.54 s

Page Load Progression

375 ms
750 ms
1.1 s
1.5 s
1.9 s
2.2 s
2.6 s
3.0 s
Checks
15
8 PASS 3 REVIEW 2 FIX
D
Third-Party Impact
Action
100% third-party, 0 ms blocking
FIX
100% third-party, 0 ms blocking
Warning::
Third-party code accounts for 100% of page weight (952.9 KiB of 953.0 KiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

C
Image Optimization
Action
18 images, 0 KB saveable
REVIEW
18 images, 0 KB saveable
Warning::
https://cdn.cbs.nl/icons/navigation/cbs-logo-brand... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://api.eu.kaltura.com/p/139/thumbnail/entry_i... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.cbs.nl/images/4f64652b416349705a534957... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.cbs.nl/images/337a6156312f6d7935784a43... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.cbs.nl/images/41735a424f73476f73774e6b... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.cbs.nl/images/324844614d3875744a694568... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.cbs.nl/images/6a48317652416a4f367a4e66... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.cbs.nl/images/5041655a61307a2f6667702f... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.cbs.nl/Content/images/placeholder.jpg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://cdn.cbs.nl/images/39416d353949583667664937... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
18 images 333 KB
0 oversized -0 KB
15 legacy format
10 missing dimensions CLS risk

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

B
JS Bundles
8 scripts, 64 KB unused
REVIEW
8 scripts, 64 KB unused
Warning::
https://cbs.containers.piwik.pro/7cd61318-6d21-477...: 34 KB unused (35%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://collect.mopinion.com/assets/surveys/2.0/js...: 29 KB unused (52%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 64 KB
64 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://cbs.containers.piwik.pro/7cd61318-6d21-4775-b1b2-64ec78d416e1.js?use_secure_cookies100 KB34 KB (35%)✓3rd
https://collect.mopinion.com/assets/surveys/2.0/js/survey.min.js?v=1808202358 KB29 KB (52%)✓3rd
https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.min.js28 KB—✓3rd
https://cdn.jsdelivr.net/npm/vanilla-lazyload@17.3.0/dist/lazyload.min.js3 KB—✓3rd
https://www.cbs.nl/content/js/cbs-v5/cbs.min.js7 KB—✓3rd
https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/js/bootstrap.bundle.min.js24 KB—✓3rd
https://deploy.mopinion.com/js/pastease.js14 KB—✓3rd
https://cbs.piwik.pro/ppms.js26 KB—✓3rd

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A
Page Weight Budget
953 KB transferred, 44 requests
PASS
953 KB transferred, 44 requests
Info::
Page weighs 1.9 MB (953 KB transferred)
Info::
44 HTTP requests
Info::
Estimated 0.20 g CO2 per page load
953 KB / 2.4 MB budget
953 KB transferred
44 requests
0.20 g CO2 per page load
Images 332.8 KiB 35%
JavaScript 259.9 KiB 27%
Fonts 197.7 KiB 21%
HTML 65.3 KiB 7%
CSS 53.3 KiB 6%
Other 27.8 KiB 3%
Other 15.3 KiB 2%
Other 966 B 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Under budget
A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+
JS Execution Cost
175ms total JS execution
PASS
175ms total JS execution
Info::
https://www.cbs.nl/: 63ms CPU time
Info::
Unattributable: 62ms CPU time
Info::
https://cbs.containers.piwik.pro/7cd61318-6d21-477...: 50ms CPU time
Warning::
Third-party scripts: 175ms (100% of total)

Main Thread Breakdown

Script Evaluation 39% Other 23% Style & Layout 20% Script Parsing & Compilation 7% Rendering 5%
ScriptTotalScriptingParse/CompileParty
https://www.cbs.nl/63ms6ms1ms3rd
Unattributable62ms2ms0ms3rd
https://cbs.containers.piwik.pro/7cd61318-6d21-4775-b1b2-64ec78d416e1.js?use_secure_cookies50ms36ms13ms3rd
A+
Font Loading
5 fonts (198 KB)
PASS
5 fonts (198 KB)
Info::
5 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

5

198 KB total

Render-blocking

0

of 5

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 500 ms 1.0 s 1.5 s FCP 990 ms LCP 1.5 shttps://cdn.cbs.nl/cdn/fonts/soho-medium.woff2soho-medium.woff2 https://cdn.cbs.nl/cdn/fonts/soho-medium.woff2 — 21.4 KiB — 225 ms — font-display: swaphttps://cdn.cbs.nl/cdn/fonts/akko-regular.woff2akko-regular.woff2 https://cdn.cbs.nl/cdn/fonts/akko-regular.woff2 — 20.5 KiB — 232 ms — font-display: swaphttps://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/fonts/fontawesome-webfont.woff2?v=4.7.0fontawesome-webfont.woff2 https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/fonts/fontawesome-webfont.woff2?v=4.7.0 — 76.0 KiB — 96 ms — font-display: swaphttps://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.5.0/fonts/fontawesome-webfont.woff2?v=4.5.0fontawesome-webfont.woff2 https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.5.0/fonts/fontawesome-webfont.woff2?v=4.5.0 — 65.7 KiB — 45 ms — font-display: swaphttps://gstatic.mopinion.com/s/opensans/v44/memSYaGs126MiZpBA-UvWbX2vVnXBbObj2OVZyOOSr4dVJWUgsjZ0B4gaVIUwaEQbjA.woff2memSYaGs126MiZpBA-UvWbX... https://gstatic.mopinion.com/s/opensans/v44/memSYaGs126MiZpBA-UvWbX2vVnXBbObj2OVZyOOSr4dVJWUgsjZ0B4gaVIUwaEQbjA.woff2 — 13.9 KiB — 125 ms — font-display: swap
soho-medium.woff2 woff2 swap
Size 21 KB
Load time 225 ms
Start 166 ms
Risk FOUT — text flashes from fallback to web font
akko-regular.woff2 woff2 swap
Size 21 KB
Load time 232 ms
Start 167 ms
Risk FOUT — text flashes from fallback to web font
fontawesome-webfont.woff2 unknown swap
Size 76 KB
Load time 96 ms
Start 167 ms
Risk FOUT — text flashes from fallback to web font
fontawesome-webfont.woff2 unknown swap
Size 66 KB
Load time 45 ms
Start 349 ms
Risk FOUT — text flashes from fallback to web font
memSYaGs126MiZpBA-UvWbX... woff2 swap
Size 14 KB
Load time 125 ms
Start 947 ms
Risk FOUT — text flashes from fallback to web font
Optimization checklist
  • Preload critical fonts (priority=high)
  • Use woff2 format for all fonts
  • Set font-display to swap, optional, or fallback
  • Subset large fonts (≤100 KB each)

Fixing the unchecked items could save ~43 KB and ~86 ms

A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
A
Page Weight Inventory
44 resources · 953 KB · 64 KB savings available
PASS
44 resources · 953 KB · 64 KB savings available
Info::
Within 1MB page-weight target
Got: 953 KB
Info::
~64 KB of savings available
Warning::
43 third-party resources (100% of weight)
44 resources · 953.0 KiB · 43 third-party Within 1MB page-weight target
Image 37% · 348.0 KiB
JavaScript 27% · 259.9 KiB
Font 21% · 197.7 KiB
Document 7% · 65.4 KiB
CSS 6% · 53.3 KiB
Other 3% · 28.7 KiB

~63.7 KiB of savings available

Remove unused JavaScript: 63.7 KiB
Network Waterfall
44 requests over 1072ms
INFO
0 ms 500 ms 1.0 s 1.5 s FCP 990 ms LCP 1.5 shttps://cbs.nl// https://cbs.nl/ — 301 — 99 B — 88 ms — h2https://www.cbs.nl/www.cbs.nl/ https://www.cbs.nl/ — 200 — 65.3 KiB — 100 ms — h2https://cdn.cbs.nl/cdn/fonts/soho-medium.woff2cdn.cbs.nl/cdn/fonts/soho-medium.wo... https://cdn.cbs.nl/cdn/fonts/soho-medium.woff2 — 200 — 21.4 KiB — 225 ms — h2https://cdn.cbs.nl/cdn/fonts/akko-regular.woff2cdn.cbs.nl/cdn/fonts/akko-regular.w... https://cdn.cbs.nl/cdn/fonts/akko-regular.woff2 — 200 — 20.5 KiB — 232 ms — h2https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/fonts/fontawesome-webfont.woff2?v=4.7.0cdnjs.cloudflare.com/ajax/libs/font... https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/fonts/fontawesome-webfont.woff2?v=4.7.0 — 200 — 76.0 KiB — 96 ms — h3https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/css/bootstrap.min.csscdn.jsdelivr.net/npm/bootstrap@5.3.... https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/css/bootstrap.min.css — 200 — 32.9 KiB — 8 ms — h2https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.csscdnjs.cloudflare.com/ajax/libs/font... https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.css — 200 — 6.4 KiB — 62 ms — h3https://www.cbs.nl/content/css-v5/cbs.min.csswww.cbs.nl/content/css-v5/cbs.min.c... https://www.cbs.nl/content/css-v5/cbs.min.css — 200 — 10.5 KiB — 33 ms — h2https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.min.jscdnjs.cloudflare.com/ajax/libs/jque... https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.min.js — 200 — 27.9 KiB — 97 ms — h3https://cdn.cbs.nl/icons/navigation/cbs-logo-brand-nl.svgcdn.cbs.nl/icons/navigation/cbs-log... https://cdn.cbs.nl/icons/navigation/cbs-logo-brand-nl.svg — 200 — 3.8 KiB — 227 ms — h2https://cdn.cbs.nl/cdn/images/site.webmanifestcdn.cbs.nl/cdn/images/site.webmanif... https://cdn.cbs.nl/cdn/images/site.webmanifest — 200 — 966 B — 226 ms — h2https://cdn.cbs.nl/images/324844614d3875744a694568663554434e62434b7a773d3d/900x450.jpgcdn.cbs.nl/images/324844614d3875744... https://cdn.cbs.nl/images/324844614d3875744a694568663554434e62434b7a773d3d/900x450.jpg — 200 — 108.8 KiB — 144 ms — h2https://www.cbs.nl/Content/images/placeholder.jpgwww.cbs.nl/Content/images/placehold... https://www.cbs.nl/Content/images/placeholder.jpg — 200 — 2.5 KiB — 39 ms — h2https://cdn.jsdelivr.net/npm/vanilla-lazyload@17.3.0/dist/lazyload.min.jscdn.jsdelivr.net/npm/vanilla-lazylo... https://cdn.jsdelivr.net/npm/vanilla-lazyload@17.3.0/dist/lazyload.min.js — 200 — 2.8 KiB — 6 ms — h2https://www.cbs.nl/content/js/cbs-v5/cbs.min.jswww.cbs.nl/content/js/cbs-v5/cbs.mi... https://www.cbs.nl/content/js/cbs-v5/cbs.min.js — 200 — 6.9 KiB — 37 ms — h2https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/js/bootstrap.bundle.min.jscdn.jsdelivr.net/npm/bootstrap@5.3.... https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/js/bootstrap.bundle.min.js — 200 — 24.0 KiB — 6 ms — h2https://api.eu.kaltura.com/p/139/thumbnail/entry_id/0_5pf53bcj/width/480/height/270/api.eu.kaltura.com/p/139/thumbnail/... https://api.eu.kaltura.com/p/139/thumbnail/entry_id/0_5pf53bcj/width/480/height/270/ — 200 — 63.6 KiB — 191 ms — http/1.1https://www.cbs.nl/content/css-v5/cbs-print.min.csswww.cbs.nl/content/css-v5/cbs-print... https://www.cbs.nl/content/css-v5/cbs-print.min.css — 200 — 1.5 KiB — 35 ms — h2https://cdn.cbs.nl/cdn/images/favicon.icocdn.cbs.nl/cdn/images/favicon.ico https://cdn.cbs.nl/cdn/images/favicon.ico — 200 — 15.2 KiB — 122 ms — h2https://cbs.containers.piwik.pro/7cd61318-6d21-4775-b1b2-64ec78d416e1.js?use_secure_cookiescbs.containers.piwik.pro/7cd61318-6... https://cbs.containers.piwik.pro/7cd61318-6d21-4775-b1b2-64ec78d416e1.js?use_secure_cookies — 200 — 100.0 KiB — 171 ms — h2https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.5.0/fonts/fontawesome-webfont.woff2?v=4.5.0cdnjs.cloudflare.com/ajax/libs/font... https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.5.0/fonts/fontawesome-webfont.woff2?v=4.5.0 — 200 — 65.7 KiB — 45 ms — h3https://deploy.mopinion.com/js/pastease.jsdeploy.mopinion.com/js/pastease.js https://deploy.mopinion.com/js/pastease.js — 200 — 13.9 KiB — 67 ms — h2https://cdn.cbs.nl/images/347674594350446a364c784579317938326d617577673d3d/294x196.jpgcdn.cbs.nl/images/347674594350446a3... https://cdn.cbs.nl/images/347674594350446a364c784579317938326d617577673d3d/294x196.jpg — -1 — 0 B — 30 ms — https://cdn.cbs.nl/images/6d4a717462566e776b745334332f6c70753468724b673d3d/294x196.jpgcdn.cbs.nl/images/6d4a717462566e776... https://cdn.cbs.nl/images/6d4a717462566e776b745334332f6c70753468724b673d3d/294x196.jpg — -1 — 0 B — 30 ms — https://cdn.cbs.nl/images/6631377a3436636b5075644f3851524c79506b7844673d3d/294x196.jpgcdn.cbs.nl/images/6631377a3436636b5... https://cdn.cbs.nl/images/6631377a3436636b5075644f3851524c79506b7844673d3d/294x196.jpg — -1 — 0 B — 30 ms — https://cdn.cbs.nl/images/6a48317652416a4f367a4e66784465394379723734673d3d/294x196.jpgcdn.cbs.nl/images/6a48317652416a4f3... https://cdn.cbs.nl/images/6a48317652416a4f367a4e66784465394379723734673d3d/294x196.jpg — 200 — 37.2 KiB — 48 ms — h2https://cdn.cbs.nl/images/4f64652b416349705a534957634a425341514a7630513d3d/294x196.jpgcdn.cbs.nl/images/4f64652b416349705... https://cdn.cbs.nl/images/4f64652b416349705a534957634a425341514a7630513d3d/294x196.jpg — 200 — 27.6 KiB — 44 ms — h2https://cdn.cbs.nl/images/337a6156312f6d7935784a4330336e64576f4c4d78413d3d/294x196.jpgcdn.cbs.nl/images/337a6156312f6d793... https://cdn.cbs.nl/images/337a6156312f6d7935784a4330336e64576f4c4d78413d3d/294x196.jpg — 200 — 23.0 KiB — 44 ms — h2https://cdn.cbs.nl/images/41735a424f73476f73774e6b354852416d347a6f68773d3d/294x196.jpgcdn.cbs.nl/images/41735a424f73476f7... https://cdn.cbs.nl/images/41735a424f73476f73774e6b354852416d347a6f68773d3d/294x196.jpg — 200 — 23.2 KiB — 57 ms — h2https://cdn.cbs.nl/images/39416d3539495836676649374654706a7869597077513d3d/294x196.jpgcdn.cbs.nl/images/39416d35394958366... https://cdn.cbs.nl/images/39416d3539495836676649374654706a7869597077513d3d/294x196.jpg — 200 — 15.0 KiB — 57 ms — h2
0 ms 500 ms 1.0 s 1.5 s FCP 990 ms LCP 1.5 shttps://cbs.nl// https://cbs.nl/ — 301 — 99 B — 88 ms — h2https://www.cbs.nl/www.cbs.nl/ https://www.cbs.nl/ — 200 — 65.3 KiB — 100 ms — h2https://cdn.cbs.nl/cdn/fonts/soho-medium.woff2cdn.cbs.nl/cdn/fonts/soho-medium.wo... https://cdn.cbs.nl/cdn/fonts/soho-medium.woff2 — 200 — 21.4 KiB — 225 ms — h2https://cdn.cbs.nl/cdn/fonts/akko-regular.woff2cdn.cbs.nl/cdn/fonts/akko-regular.w... https://cdn.cbs.nl/cdn/fonts/akko-regular.woff2 — 200 — 20.5 KiB — 232 ms — h2https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/fonts/fontawesome-webfont.woff2?v=4.7.0cdnjs.cloudflare.com/ajax/libs/font... https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/fonts/fontawesome-webfont.woff2?v=4.7.0 — 200 — 76.0 KiB — 96 ms — h3https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/css/bootstrap.min.csscdn.jsdelivr.net/npm/bootstrap@5.3.... https://cdn.jsdelivr.net/npm/bootstrap@5.3.3/dist/css/bootstrap.min.css — 200 — 32.9 KiB — 8 ms — h2https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.csscdnjs.cloudflare.com/ajax/libs/font... https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.css — 200 — 6.4 KiB — 62 ms — h3https://www.cbs.nl/content/css-v5/cbs.min.csswww.cbs.nl/content/css-v5/cbs.min.c... https://www.cbs.nl/content/css-v5/cbs.min.css — 200 — 10.5 KiB — 33 ms — h2https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.min.jscdnjs.cloudflare.com/ajax/libs/jque... https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.min.js — 200 — 27.9 KiB — 97 ms — h3https://cdn.cbs.nl/icons/navigation/cbs-logo-brand-nl.svgcdn.cbs.nl/icons/navigation/cbs-log... https://cdn.cbs.nl/icons/navigation/cbs-logo-brand-nl.svg — 200 — 3.8 KiB — 227 ms — h2https://cdn.cbs.nl/cdn/images/site.webmanifestcdn.cbs.nl/cdn/images/site.webmanif... https://cdn.cbs.nl/cdn/images/site.webmanifest — 200 — 966 B — 226 ms — 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ms — h2https://api.eu.kaltura.com/p/139/thumbnail/entry_id/0_5pf53bcj/width/480/height/270/api.eu.kaltura.com/p/139/thumbnail/... https://api.eu.kaltura.com/p/139/thumbnail/entry_id/0_5pf53bcj/width/480/height/270/ — 200 — 63.6 KiB — 191 ms — http/1.1https://www.cbs.nl/content/css-v5/cbs-print.min.csswww.cbs.nl/content/css-v5/cbs-print... https://www.cbs.nl/content/css-v5/cbs-print.min.css — 200 — 1.5 KiB — 35 ms — h2https://cdn.cbs.nl/cdn/images/favicon.icocdn.cbs.nl/cdn/images/favicon.ico https://cdn.cbs.nl/cdn/images/favicon.ico — 200 — 15.2 KiB — 122 ms — h2https://cbs.containers.piwik.pro/7cd61318-6d21-4775-b1b2-64ec78d416e1.js?use_secure_cookiescbs.containers.piwik.pro/7cd61318-6... https://cbs.containers.piwik.pro/7cd61318-6d21-4775-b1b2-64ec78d416e1.js?use_secure_cookies — 200 — 100.0 KiB — 171 ms — h2https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.5.0/fonts/fontawesome-webfont.woff2?v=4.5.0cdnjs.cloudflare.com/ajax/libs/font... 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HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100% of JavaScript execution is third-party
First-party Third-party 175ms · 165KB · €2/mo
www.cbs.nl
Other
Optional
Execution 63ms
Transfer 65 KB
Monthly Cost €1/mo
Unattributable
Other
Optional
Execution 62ms
Transfer 0 KB
Monthly Cost €1/mo
cbs.containers.piwik.pro
Other
Optional
Execution 50ms
Transfer 100 KB
Unused 35%
Monthly Cost €1/mo

100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.

Why this matters

When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.

Learn more ▾

Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.

Source: web.dev

How third-party costs are calculated

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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