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Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
84
GRADE
B
FIX
2
REVIEW
5
PASS
6
INFO
2

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

Mobile Desktop
79
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
87
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
85
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
91
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.

1.48 s

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

2.82 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.

0.000

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

1.48 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.

2.82 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
6 PASS 5 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 (1.6 MiB of 1.6 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
D
Page Weight Inventory
Action
25 resources · 1.6 MB · 82 KB savings available
FIX
25 resources · 1.6 MB · 82 KB savings available
Warning::
Page weight 641 KB over 1MB target
Got: 1.6 MB Expected: ≤ 1 MB
Info::
~82 KB of savings available
Warning::
24 third-party resources (100% of weight)
Info::
1 resources over 200KB
25 resources · 1.6 MiB · 24 third-party 640.9 KiB over 1MB target
Image 68% · 1.1 MiB
CSS 15% · 242.2 KiB
JavaScript 14% · 230.3 KiB
Font 3% · 55.9 KiB
Document 1% · 10.0 KiB
Other 0% · 1.2 KiB

~82.0 KiB of savings available

Remove unused JavaScript: 82.0 KiB
C
Page Weight Budget
Action
1.6 MB transferred, 25 requests
REVIEW
1.6 MB transferred, 25 requests
Info::
Page weighs 2.1 MB (1.6 MB transferred)
Warning::
Images are 1.1 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 1.1 MB
Info::
CSS is 242 KB — consider purging unused styles
Remove unused CSS rules with tools like PurgeCSS to reduce stylesheet size.
Got: 242 KB
Info::
25 HTTP requests
Info::
Estimated 0.34 g CO2 per page load
1.6 MB / 2.4 MB budget
1.6 MB transferred
25 requests
0.34 g CO2 per page load
Images 1.1 MiB 68%
CSS 242.2 KiB 15%
JavaScript 230.3 KiB 14%
Fonts 55.9 KiB 3%
HTML 10.0 KiB 1%
Other 1.0 KiB 0%
Other 546 B 0%
Other 462 B 0%
0 2.4 MB 4.9 MB
Approaching limit

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Why this matters

Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.

Source: web.dev

Remove unused CSS rules with tools like PurgeCSS to reduce stylesheet size.

Why this matters

CSS bundle is large — purge unused styles (PurgeCSS, Tailwind JIT) to reduce CSS payload.

Source: web.dev

B
Image Optimization
5 images, 0 KB saveable
REVIEW
5 images, 0 KB saveable
Warning::
https://www.un.org/en/img/splash/un-logo.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
5 images 1.1 MB
0 oversized -0 KB
5 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

B
JS Bundles
5 scripts, 82 KB unused
REVIEW
5 scripts, 82 KB unused
Warning::
https://www.googletagmanager.com/gtag/js?id=G-TK9B...: 61 KB unused (39%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://code.jquery.com/jquery-3.7.1.min.js: 21 KB unused (70%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 82 KB
82 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.googletagmanager.com/gtag/js?id=G-TK9BQL5X7Z&cx=c&_slc=1156 KB61 KB (39%)✓3rd
https://code.jquery.com/jquery-3.7.1.min.js30 KB21 KB (70%)✓3rd
https://www.un.org/fr/images/splash/splash.js6 KB—✓3rd
https://ssl.google-analytics.com/ga.js17 KB—✓3rd
https://www.google-analytics.com/analytics.js21 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

B
HTTP Caching
no-cache
REVIEW
no-cache
Info::
Cache-Control header is set
Got: no-cache
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

no-cache

DirectiveValueMeaning
no-cache—Cache but always revalidate first
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
197ms total JS execution
PASS
197ms total JS execution
Info::
https://www.un.org/: 144ms CPU time
Info::
Unattributable: 53ms CPU time
Warning::
Third-party scripts: 197ms (100% of total)

Main Thread Breakdown

Other 50% Script Evaluation 29% Style & Layout 12% Script Parsing & Compilation 5%
ScriptTotalScriptingParse/CompileParty
https://www.un.org/144ms1ms0ms3rd
Unattributable53ms16ms0ms3rd
A+
Font Loading
2 fonts (56 KB)
PASS
2 fonts (56 KB)
Info::
2 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

2

56 KB total

Render-blocking

0

of 2

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 2.0 s 2.5 s FCP 1.5 s LCP 2.8 shttps://fonts.gstatic.com/s/roboto/v51/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2KFO7CnqEu92Fr1ME7kSn66a... https://fonts.gstatic.com/s/roboto/v51/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2 — 36.7 KiB — 88 ms — font-display: swaphttps://fonts.gstatic.com/s/roboto/v51/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3iUBHMdazTgWw.woff2KFO7CnqEu92Fr1ME7kSn66a... https://fonts.gstatic.com/s/roboto/v51/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3iUBHMdazTgWw.woff2 — 19.2 KiB — 75 ms — font-display: swap
KFO7CnqEu92Fr1ME7kSn66a... woff2 swap
Size 37 KB
Load time 88 ms
Start 814 ms
Risk FOUT — text flashes from fallback to web font
KFO7CnqEu92Fr1ME7kSn66a... woff2 swap
Size 19 KB
Load time 75 ms
Start 814 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)
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
Network Waterfall
25 requests over 1281ms
INFO
0 ms 500 ms 1.0 s 1.5 s 2.0 s 2.5 s FCP 1.5 s LCP 2.8 shttps://un.org// https://un.org/ — 302 — 199 B — 431 ms — http/1.1https://www.un.org/www.un.org/ https://www.un.org/ — 200 — 10.0 KiB — 158 ms — h2https://www.un.org/en/events/global-assets/bootstrap-3.3.5-dist/css/bootstrap.min.csswww.un.org/en/events/global-assets/... https://www.un.org/en/events/global-assets/bootstrap-3.3.5-dist/css/bootstrap.min.css — 200 — 120.4 KiB — 61 ms — h2https://www.un.org/en/events/global-assets/bootstrap-3.3.5-dist/css/bootstrap-theme.min.csswww.un.org/en/events/global-assets/... https://www.un.org/en/events/global-assets/bootstrap-3.3.5-dist/css/bootstrap-theme.min.css — 200 — 23.4 KiB — 28 ms — h2https://maxcdn.bootstrapcdn.com/font-awesome/4.6.3/css/font-awesome.min.cssmaxcdn.bootstrapcdn.com/font-awesom... https://maxcdn.bootstrapcdn.com/font-awesome/4.6.3/css/font-awesome.min.css — 200 — 7.0 KiB — 46 ms — h3https://fonts.googleapis.com/css?family=Roboto:400,100,100italic,300,300italic,400italic,500,500italic,700,700italic,900,900italicfonts.googleapis.com/css?family=Rob... https://fonts.googleapis.com/css?family=Roboto:400,100,100italic,300,300italic,400italic,500,500italic,700,700italic,900,900italic — 200 — 2.9 KiB — 184 ms — h2https://www.un.org/en/events/global-assets/css/flying-focus.csswww.un.org/en/events/global-assets/... https://www.un.org/en/events/global-assets/css/flying-focus.css — 200 — 1.5 KiB — 60 ms — h2https://www.un.org/fr/images/splash/animate.csswww.un.org/fr/images/splash/animate... https://www.un.org/fr/images/splash/animate.css — 200 — 77.5 KiB — 67 ms — h2https://www.un.org/fr/images/splash/splash-specific.csswww.un.org/fr/images/splash/splash-... https://www.un.org/fr/images/splash/splash-specific.css — 200 — 8.9 KiB — 69 ms — h2https://www.un.org/fr/images/splash/image-position-mobile.csswww.un.org/fr/images/splash/image-p... https://www.un.org/fr/images/splash/image-position-mobile.css — 200 — 730 B — 70 ms — h2https://code.jquery.com/jquery-3.7.1.min.jscode.jquery.com/jquery-3.7.1.min.js https://code.jquery.com/jquery-3.7.1.min.js — 200 — 30.0 KiB — 37 ms — h2https://www.un.org/images/splash/Flag.jpgwww.un.org/images/splash/Flag.jpg https://www.un.org/images/splash/Flag.jpg — 200 — 1.1 MiB — 108 ms — h2https://www.un.org/en/img/splash/un-logo.pngwww.un.org/en/img/splash/un-logo.pn... https://www.un.org/en/img/splash/un-logo.png — 200 — 9.1 KiB — 94 ms — h2https://www.un.org/fr/images/splash/splash.jswww.un.org/fr/images/splash/splash.... https://www.un.org/fr/images/splash/splash.js — 200 — 6.3 KiB — 21 ms — h2https://ssl.google-analytics.com/ga.jsssl.google-analytics.com/ga.js https://ssl.google-analytics.com/ga.js — 200 — 17.4 KiB — 131 ms — h2https://www.google-analytics.com/analytics.jswww.google-analytics.com/analytics.... https://www.google-analytics.com/analytics.js — 200 — 20.9 KiB — 133 ms — h2https://www.un.org/en/img/splash/questionmark.pngwww.un.org/en/img/splash/questionma... https://www.un.org/en/img/splash/questionmark.png — 200 — 1.0 KiB — 21 ms — h2https://www.un.org/en/img/splash/copyright.pngwww.un.org/en/img/splash/copyright.... https://www.un.org/en/img/splash/copyright.png — 200 — 2.4 KiB — 22 ms — h2https://www.un.org/en/img/splash/white-stripe.jpgwww.un.org/en/img/splash/white-stri... https://www.un.org/en/img/splash/white-stripe.jpg — 404 — 210 B — 327 ms — h2https://fonts.gstatic.com/s/roboto/v51/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2fonts.gstatic.com/s/roboto/v51/KFO7... https://fonts.gstatic.com/s/roboto/v51/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2 — 200 — 36.7 KiB — 88 ms — h3https://fonts.gstatic.com/s/roboto/v51/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3iUBHMdazTgWw.woff2fonts.gstatic.com/s/roboto/v51/KFO7... https://fonts.gstatic.com/s/roboto/v51/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3iUBHMdazTgWw.woff2 — 200 — 19.2 KiB — 75 ms — h3https://www.google-analytics.com/j/collect?v=1&_v=j102&aip=1&a=1746111292&t=pageview&_s=1&dl=https%3A%2F%2Fwww.un.org%2F&ul=en-us&dt=Welcome%20to%20the%20United%20Nations&sr=800x600&vp=1350x940&_u=YEBAAEABAAAAACAAI~&jid=1044183382&gjid=1998678725&cid=1787469506.1776360335&tid=UA-4803886-1&_gid=1290070623.1776360335&_r=1&_slc=1&z=639092811www.google-analytics.com/j/collect?... https://www.google-analytics.com/j/collect?v=1&_v=j102&aip=1&a=1746111292&t=pageview&_s=1&dl=https%3A%2F%2Fwww.un.org%2F&ul=en-us&dt=Welcome%20to%20the%20United%20Nations&sr=800x600&vp=1350x940&_u=YEBAAEABAAAAACAAI~&jid=1044183382&gjid=1998678725&cid=1787469506.1776360335&tid=UA-4803886-1&_gid=1290070623.1776360335&_r=1&_slc=1&z=639092811 — 200 — 462 B — 53 ms — h2https://www.googletagmanager.com/gtag/js?id=G-TK9BQL5X7Z&cx=c&_slc=1www.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=G-TK9BQL5X7Z&cx=c&_slc=1 — 200 — 155.7 KiB — 146 ms — h2https://region1.google-analytics.com/g/collect?v=2&tid=G-TK9BQL5X7Z&gtm=45je64f0v870000365za20g&_p=1776360334649&gcd=13l3lPl2l2l1&npa=0&dma_cps=a&dma=1&_eu=ABAI&are=1&cid=1787469506.1776360335&frm=0&pscdl=noapi&rcb=19&sr=800x600&uaa=x86&uab=64&uafvl=Chromium%3B147.0.7727.55%7CNot.A%252FBrand%3B8.0.0.0&uam=&uamb=0&uap=macOS&uapv=10.15.7&uaw=0&ul=en-us&_s=1&tag_exp=0~115616985~115938466~115938469~117266401~118131810&dl=https%3A%2F%2Fwww.un.org%2F&dt=Welcome%20to%20the%20United%20Nations&sid=1776360334&sct=1&seg=0&_tu=wAQ&en=page_view&_fv=1&_ss=1&_ee=1&tfd=1215region1.google-analytics.com/g/coll... https://region1.google-analytics.com/g/collect?v=2&tid=G-TK9BQL5X7Z&gtm=45je64f0v870000365za20g&_p=1776360334649&gcd=13l3lPl2l2l1&npa=0&dma_cps=a&dma=1&_eu=ABAI&are=1&cid=1787469506.1776360335&frm=0&pscdl=noapi&rcb=19&sr=800x600&uaa=x86&uab=64&uafvl=Chromium%3B147.0.7727.55%7CNot.A%252FBrand%3B8.0.0.0&uam=&uamb=0&uap=macOS&uapv=10.15.7&uaw=0&ul=en-us&_s=1&tag_exp=0~115616985~115938466~115938469~117266401~118131810&dl=https%3A%2F%2Fwww.un.org%2F&dt=Welcome%20to%20the%20United%20Nations&sid=1776360334&sct=1&seg=0&_tu=wAQ&en=page_view&_fv=1&_ss=1&_ee=1&tfd=1215 — 204 — 546 B — 66 ms — h2https://www.un.org/sites/un2.un.org/themes/bootstrap_un2/favicon.icowww.un.org/sites/un2.un.org/themes/... https://www.un.org/sites/un2.un.org/themes/bootstrap_un2/favicon.ico — 200 — 849 B — 21 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 197ms · 10KB · $3/mo
www.un.org
Other
Optional
Execution 144ms
Transfer 10 KB
Monthly Cost $2/mo
Unattributable
Other
Optional
Execution 53ms
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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