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Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
85
GRADE
B
FIX
1
REVIEW
4
PASS
7
INFO
2

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

Mobile Desktop
55
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.
81
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.

3.78 s

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

15.23 s

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

335 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.

6.26 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.

15.23 s

Page Load Progression

586 ms
1.2 s
1.8 s
2.3 s
2.9 s
3.5 s
4.1 s
4.7 s
Checks
14
7 PASS 4 REVIEW 1 FIX
D
Page Weight Budget
Action
2.5 MB transferred, 24 requests
FIX
2.5 MB transferred, 24 requests
Warning::
Page weighs 2.9 MB (2.5 MB transferred)
Warning::
Images are 1.9 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 1.9 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::
24 HTTP requests
Info::
Estimated 0.52 g CO2 per page load
2.5 MB / 2.4 MB budget
2.5 MB transferred
24 requests
0.52 g CO2 per page load
Images 1.9 MiB 79%
CSS 242.2 KiB 10%
JavaScript 227.0 KiB 9%
Fonts 55.9 KiB 2%
HTML 10.5 KiB 0%
Other 850 B 0%
Other 545 B 0%
Other 462 B 0%
0 2.4 MB 4.9 MB
Over budget

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 1.9 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

C
JS Execution Cost
Action
1546ms total JS execution
REVIEW
1546ms total JS execution
Warning::
Unattributable: 492ms CPU time
Warning::
https://www.googletagmanager.com/gtag/js?id=G-TK9B...: 377ms CPU time
Warning::
https://www.un.org/: 344ms CPU time
Warning::
https://www.google-analytics.com/analytics.js: 250ms CPU time
Info::
https://code.jquery.com/jquery-3.7.1.min.js: 83ms CPU time
Warning::
Third-party scripts: 1202ms (78% of total)

Main Thread Breakdown

Other 36% Script Evaluation 35% Style & Layout 14% Script Parsing & Compilation 7% Parse HTML & CSS 4%
ScriptTotalScriptingParse/CompileParty
Unattributable492ms112ms0ms3rd
https://www.googletagmanager.com/gtag/js?id=G-TK9BQL5X7Z&cx=c&_slc=1377ms283ms84ms3rd
https://www.un.org/344ms12ms3ms1st
https://www.google-analytics.com/analytics.js250ms104ms9ms3rd
https://code.jquery.com/jquery-3.7.1.min.js83ms61ms14ms3rd
B
JS Bundles
5 scripts, 81 KB unused
REVIEW
5 scripts, 81 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: 20 KB unused (69%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 81 KB
81 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.googletagmanager.com/gtag/js?id=G-TK9BQL5X7Z&cx=c&_slc=1154 KB61 KB (39%)✓3rd
https://code.jquery.com/jquery-3.7.1.min.js30 KB20 KB (69%)✓3rd
https://ssl.google-analytics.com/ga.js15 KB—✓3rd
https://www.un.org/fr/images/splash/splash.js6 KB—✓1st
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

A+
Third-Party Impact
11% third-party, 0 ms blocking
PASS
11% third-party, 0 ms blocking
Info::
Third-party code accounts for 11% of page weight (287.4 KiB of 2.5 MiB)
Info::
Third-party blocking time is low (0 ms)
89%
First-party Third-party
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+
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 2.0 s 4.0 s 6.0 s 8.0 s 10.0 s 12.0 s 14.0 s FCP 3.8 s LCP 15.2 shttps://fonts.gstatic.com/s/roboto/v51/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2KFO7CnqEu92Fr1ME7kSn66a... https://fonts.gstatic.com/s/roboto/v51/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2 — 36.7 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/roboto/v51/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3iUBHMdazTgWw.woff2KFO7CnqEu92Fr1ME7kSn66a... https://fonts.gstatic.com/s/roboto/v51/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3iUBHMdazTgWw.woff2 — 19.2 KiB — 0 ms — font-display: swap
KFO7CnqEu92Fr1ME7kSn66a... woff2 swap
Size 37 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
KFO7CnqEu92Fr1ME7kSn66a... woff2 swap
Size 19 KB
Load time 0 ms
Start 0 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
A+
HTTP Caching
max-age=900 (15 minutes)
PASS
max-age=900 (15 minutes)
Info::
Cache-Control header is set
Got: public, max-age=900
Info::
Effective TTL: 15 minutes (max-age=900)
Info::
ETag present — enables conditional (304) responses
Info::
Last-Modified header present
Cache-Control

public, max-age=900

DirectiveValueMeaning
public—Any cache may store this response
max-age900Cache for 15 minutes
Effective TTL: 900 seconds
Network Waterfall
24 requests over 0ms
INFO

Performance analysis not available for this result.

Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
78% of JavaScript execution is third-party
First-party Third-party 1202ms · 205KB · €13/mo
Unattributable
Other
Costly
Execution 492ms
Transfer 0 KB
Monthly Cost €5/mo
Google Tag Manager
Tag Manager
Costly
Execution 377ms
Transfer 154 KB
Unused 39%
Monthly Cost €4/mo
Google Analytics
Analytics
Costly
Execution 250ms
Transfer 21 KB
Monthly Cost €3/mo
code.jquery.com
Other
Optional
Execution 83ms
Transfer 30 KB
Unused 69%
Monthly Cost €1/mo

These scripts may cost more than they're worth

  • Unattributable adds 492ms and costs ~€5/month
  • Google Tag Manager adds 377ms and costs ~€4/month
  • Google Analytics adds 250ms and costs ~€3/month

78% 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

Unattributable takes 492ms 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

Google Tag Manager takes 377ms 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

Google Analytics takes 250ms 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

69% of code.jquery.com's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

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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