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https://nu.nl

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
90
GRADE
A
FIX
2
REVIEW
3
PASS
10
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.
98
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.
50
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.

2.34 s

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

3.21 s

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

229 ms

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

0.000

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

2.34 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.

3.94 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
17
10 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 (192.1 KiB of 192.8 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.

B
JS Execution Cost
834ms total JS execution
REVIEW
834ms total JS execution
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-NT4...: 333ms CPU time
Info::
https://myprivacy-static.dpgmedia.net/consent.js: 218ms CPU time
Info::
Unattributable: 127ms CPU time
Info::
https://myprivacy.dpgmedia.nl/consent?siteKey=ucf9...: 80ms CPU time
Info::
https://sp.dpgmedia.net/X9MmT8zP6LqV4RdK7Jw_v4_4_0...: 76ms CPU time
Warning::
Third-party scripts: 834ms (100% of total)

Main Thread Breakdown

Script Evaluation 60% Other 18% Script Parsing & Compilation 9% Style & Layout 8%
ScriptTotalScriptingParse/CompileParty
https://www.googletagmanager.com/gtm.js?id=GTM-NT4WR7C333ms282ms39ms3rd
https://myprivacy-static.dpgmedia.net/consent.js218ms143ms28ms3rd
Unattributable127ms8ms0ms3rd
https://myprivacy.dpgmedia.nl/consent?siteKey=ucf98legs1caotgh&callbackUrl=https%3A%2F%2Fnu.nl%2Fprivacy-gate%2Faccept%3FredirectUri%3D%252F&isLoggedIn=false80ms6ms2ms3rd
https://sp.dpgmedia.net/X9MmT8zP6LqV4RdK7Jw_v4_4_0.js76ms64ms7ms3rd
B
JS Bundles
3 scripts, 59 KB unused
REVIEW
3 scripts, 59 KB unused
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-NT4...: 59 KB unused (46%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 59 KB
59 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.googletagmanager.com/gtm.js?id=GTM-NT4WR7C129 KB59 KB (46%)✓3rd
https://myprivacy-static.dpgmedia.net/consent.js0 KB—✓3rd
https://sp.dpgmedia.net/X9MmT8zP6LqV4RdK7Jw_v4_4_0.js25 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

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

Green Hosting

No green hosting detected

A+
Page Weight Budget
193 KB transferred, 15 requests
PASS
193 KB transferred, 15 requests
Info::
Page weighs 887 KB (193 KB transferred)
Info::
15 HTTP requests
Info::
Estimated 0.04 g CO2 per page load
193 KB / 2.4 MB budget
193 KB transferred
15 requests
0.04 g CO2 per page load
JavaScript 154.0 KiB 80%
Other 19.0 KiB 10%
Images 10.3 KiB 5%
Other 6.1 KiB 3%
HTML 3.4 KiB 2%
Other 18 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
Image Optimization
3 images, 0 KB saveable
PASS
3 images, 0 KB saveable
Warning::
https://myprivacy-static.dpgmedia.net/consent/reso... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
3 images 10 KB
0 oversized -0 KB
2 legacy format
1 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

A+
Font Loading
No web fonts (system fonts)
PASS
No web fonts (system fonts)
Info::
No web fonts loaded — system fonts are fastest
No web fonts loaded — system fonts are optimal.
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
19 hints, 0 missing preconnects
PASS
19 hints, 0 missing preconnects
Info::
Page uses 19 resource hint(s)

Current Resource Hints

preconnect
9
preload
1
dns-prefetch
9
prefetch
—

19 resource hints configured

A
Page Weight Inventory
15 resources · 193 KB · 59 KB savings available
PASS
15 resources · 193 KB · 59 KB savings available
Info::
Within 1MB page-weight target
Got: 193 KB
Info::
~59 KB of savings available
Warning::
14 third-party resources (100% of weight)
15 resources · 192.8 KiB · 14 third-party Within 1MB page-weight target
JavaScript 80% · 154.0 KiB
Other 10% · 19.0 KiB
Image 8% · 15.8 KiB
Document 2% · 4.0 KiB

~58.9 KiB of savings available

Remove unused JavaScript: 58.9 KiB
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
Network Waterfall
15 requests over 756ms
INFO
0 ms 1.0 s 2.0 s 3.0 s FCP 2.3 s LCP 3.2 shttps://nu.nl// https://nu.nl/ — 302 — 646 B — 28 ms — h2https://myprivacy.dpgmedia.nl/consent?siteKey=ucf98legs1caotgh&callbackUrl=https%3A%2F%2Fnu.nl%2Fprivacy-gate%2Faccept%3FredirectUri%3D%252F&isLoggedIn=falsemyprivacy.dpgmedia.nl/consent?siteK... https://myprivacy.dpgmedia.nl/consent?siteKey=ucf98legs1caotgh&callbackUrl=https%3A%2F%2Fnu.nl%2Fprivacy-gate%2Faccept%3FredirectUri%3D%252F&isLoggedIn=false — 200 — 3.4 KiB — 37 ms — h2https://myprivacy-static.dpgmedia.net/consent.jsmyprivacy-static.dpgmedia.net/conse... https://myprivacy-static.dpgmedia.net/consent.js — 200 — 0 B — 55 ms — h2https://myprivacy-static.dpgmedia.net/consent/resources/logos/logo-dpgmedia.svgmyprivacy-static.dpgmedia.net/conse... https://myprivacy-static.dpgmedia.net/consent/resources/logos/logo-dpgmedia.svg — 200 — 2.5 KiB — 46 ms — h2https://www.googletagmanager.com/gtm.js?id=GTM-NT4WR7Cwww.googletagmanager.com/gtm.js?id=... https://www.googletagmanager.com/gtm.js?id=GTM-NT4WR7C — 200 — 129.1 KiB — 177 ms — h2https://myprivacy-static.dpgmedia.net/consent/resources/backgrounds/small/nu.webpmyprivacy-static.dpgmedia.net/conse... https://myprivacy-static.dpgmedia.net/consent/resources/backgrounds/small/nu.webp — 200 — 6.9 KiB — 15 ms — h2https://pg.dpgmedia.nl/api/consent?language=nl&siteUrl=https%3A%2F%2Fnu.nl&readOnly=false&authId=d7c479fb-1fda-42da-8924-925ff22decc4&integratorId=nu-nlpg.dpgmedia.nl/api/consent?language... https://pg.dpgmedia.nl/api/consent?language=nl&siteUrl=https%3A%2F%2Fnu.nl&readOnly=false&authId=d7c479fb-1fda-42da-8924-925ff22decc4&integratorId=nu-nl — 200 — 952 B — 83 ms — h2https://myprivacy-static.dpgmedia.net/integrator-config/nu-nl-nl.jsonmyprivacy-static.dpgmedia.net/integ... https://myprivacy-static.dpgmedia.net/integrator-config/nu-nl-nl.json — 200 — 17.7 KiB — 15 ms — h3https://pg.dpgmedia.net/api/metricspg.dpgmedia.net/api/metrics https://pg.dpgmedia.net/api/metrics — 200 — 0 B — 68 ms — h2https://myprivacy-static.dpgmedia.net/consent/resources/logos/logo-nu.svgmyprivacy-static.dpgmedia.net/conse... https://myprivacy-static.dpgmedia.net/consent/resources/logos/logo-nu.svg — 200 — 916 B — 11 ms — h3https://pg.dpgmedia.net/api/metricspg.dpgmedia.net/api/metrics https://pg.dpgmedia.net/api/metrics — 200 — 18 B — 92 ms — h3https://sp.dpgmedia.net/X9MmT8zP6LqV4RdK7Jw_v4_4_0.jssp.dpgmedia.net/X9MmT8zP6LqV4RdK7Jw... https://sp.dpgmedia.net/X9MmT8zP6LqV4RdK7Jw_v4_4_0.js — 200 — 24.9 KiB — 62 ms — h2https://c.dpgmedia.net/a/bc.dpgmedia.net/a/b https://c.dpgmedia.net/a/b — 200 — 0 B — 172 ms — h2https://myprivacy.dpgmedia.nl/favicon.icomyprivacy.dpgmedia.nl/favicon.ico https://myprivacy.dpgmedia.nl/favicon.ico — 200 — 5.5 KiB — 19 ms — h2https://c.dpgmedia.net/a/bc.dpgmedia.net/a/b https://c.dpgmedia.net/a/b — 200 — 311 B — 104 ms — h2
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 834ms · 157KB · €9/mo
Google Tag Manager
Tag Manager
Costly
Execution 333ms
Transfer 129 KB
Unused 46%
Monthly Cost €4/mo
myprivacy-static.dpgmedia.net
Other
Costly
Execution 218ms
Transfer 0 KB
Monthly Cost €2/mo
Unattributable
Other
Optional
Execution 127ms
Transfer 0 KB
Monthly Cost €1/mo
myprivacy.dpgmedia.nl
Other
Optional
Execution 80ms
Transfer 3 KB
Monthly Cost €1/mo
sp.dpgmedia.net
Other
Optional
Execution 76ms
Transfer 25 KB
Monthly Cost €1/mo

These scripts may cost more than they're worth

  • Google Tag Manager adds 333ms and costs ~€4/month
  • myprivacy-static.dpgmedia.net adds 218ms and costs ~€2/month

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

Google Tag Manager takes 333ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

myprivacy-static.dpgmedia.net takes 218ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

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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