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https://nu.nl

Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
90
GRADE
A
FIX
2
REVIEW
2
PASS
9
INFO
2

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

Mobile Desktop
99
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.

679 ms

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

969 ms

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

18 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.

679 ms

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

1.11 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
9 PASS 2 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 (248.3 KiB of 248.9 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 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
249 KB transferred, 15 requests
PASS
249 KB transferred, 15 requests
Info::
Page weighs 946 KB (249 KB transferred)
Info::
15 HTTP requests
Info::
Estimated 0.05 g CO2 per page load
249 KB / 2.4 MB budget
249 KB transferred
15 requests
0.05 g CO2 per page load
JavaScript 154.0 KiB 62%
Images 66.5 KiB 27%
Other 19.0 KiB 8%
Other 6.1 KiB 2%
HTML 3.4 KiB 1%
Other 19 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 66 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+
JS Execution Cost
156ms total JS execution
PASS
156ms total JS execution
Info::
https://www.googletagmanager.com/gtm.js?id=GTM-NT4...: 99ms CPU time
Info::
https://myprivacy-static.dpgmedia.net/consent.js: 57ms CPU time
Warning::
Third-party scripts: 156ms (100% of total)

Main Thread Breakdown

Script Evaluation 64% Other 17% Script Parsing & Compilation 8% Style & Layout 7%
ScriptTotalScriptingParse/CompileParty
https://www.googletagmanager.com/gtm.js?id=GTM-NT4WR7C99ms87ms11ms3rd
https://myprivacy-static.dpgmedia.net/consent.js57ms40ms5ms3rd
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
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
A
Page Weight Inventory
15 resources · 249 KB · 59 KB savings available
PASS
15 resources · 249 KB · 59 KB savings available
Info::
Within 1MB page-weight target
Got: 249 KB
Info::
~59 KB of savings available
Warning::
14 third-party resources (100% of weight)
15 resources · 248.9 KiB · 14 third-party Within 1MB page-weight target
JavaScript 62% · 154.0 KiB
Image 29% · 72.0 KiB
Other 8% · 19.0 KiB
Document 2% · 4.0 KiB

~58.9 KiB of savings available

Remove unused JavaScript: 58.9 KiB
Network Waterfall
15 requests over 659ms
INFO
0 ms 500 ms 1.0 s FCP 679 ms LCP 969 mshttps://nu.nl// https://nu.nl/ — 302 — 647 B — 43 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 — 26 ms — h2https://myprivacy-static.dpgmedia.net/consent.jsmyprivacy-static.dpgmedia.net/conse... https://myprivacy-static.dpgmedia.net/consent.js — 200 — 0 B — 23 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 — 12 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 — 169 ms — h2https://myprivacy-static.dpgmedia.net/consent/resources/backgrounds/nu.webpmyprivacy-static.dpgmedia.net/conse... https://myprivacy-static.dpgmedia.net/consent/resources/backgrounds/nu.webp — 200 — 63.1 KiB — 15 ms — h2https://pg.dpgmedia.nl/api/consent?language=nl&siteUrl=https%3A%2F%2Fnu.nl&readOnly=false&authId=fa418345-3b1e-4ceb-9ecd-71ce09bf513a&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=fa418345-3b1e-4ceb-9ecd-71ce09bf513a&integratorId=nu-nl — 200 — 951 B — 79 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 — 28 ms — h3https://pg.dpgmedia.net/api/metricspg.dpgmedia.net/api/metrics https://pg.dpgmedia.net/api/metrics — 200 — 0 B — 29 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 — 17 ms — h3https://pg.dpgmedia.net/api/metricspg.dpgmedia.net/api/metrics https://pg.dpgmedia.net/api/metrics — 200 — 19 B — 75 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 — 14 ms — h2https://c.dpgmedia.net/a/bc.dpgmedia.net/a/b https://c.dpgmedia.net/a/b — 200 — 0 B — 141 ms — h2https://myprivacy.dpgmedia.nl/favicon.icomyprivacy.dpgmedia.nl/favicon.ico https://myprivacy.dpgmedia.nl/favicon.ico — 200 — 5.5 KiB — 16 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 156ms · 129KB · €2/mo
Google Tag Manager
Tag Manager
Optional
Execution 99ms
Transfer 129 KB
Unused 46%
Monthly Cost €1/mo
myprivacy-static.dpgmedia.net
Other
Optional
Execution 57ms
Transfer 0 KB
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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