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https://www.wikimedia.org

Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
95
GRADE
A
FIX
0
REVIEW
2
PASS
10
INFO
2

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

Mobile Desktop
100
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
84
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.
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.

249 ms

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

444 ms

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.

249 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.

444 ms

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
14
10 PASS 2 REVIEW
B
Image Optimization
18 images, 0 KB saveable
REVIEW
18 images, 0 KB saveable
Warning::
https://www.wikimedia.org/portal/wikimedia.org/ass... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
18 images 211 KB
0 oversized -0 KB
18 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
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Page Weight Budget
229 KB transferred, 21 requests
PASS
229 KB transferred, 21 requests
Info::
Page weighs 469 KB (229 KB transferred)
Info::
21 HTTP requests
Info::
Estimated 0.05 g CO2 per page load
229 KB / 2.4 MB budget
229 KB transferred
21 requests
0.05 g CO2 per page load
Images 210.9 KiB 92%
HTML 11.1 KiB 5%
JavaScript 3.7 KiB 2%
Other 3.6 KiB 2%
0 2.4 MB 4.9 MB
Under budget
A+
Third-Party Impact
2% third-party, 0 ms blocking
PASS
2% third-party, 0 ms blocking
Info::
Third-party code accounts for 2% of page weight (3.6 KiB of 229.3 KiB)
Info::
Third-party blocking time is low (0 ms)
98%
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+
JS Execution Cost
100ms total JS execution
PASS
100ms total JS execution
Info::
Unattributable: 100ms CPU time
Warning::
Third-party scripts: 100ms (100% of total)

Main Thread Breakdown

Other 66% Style & Layout 21% Rendering 5% Script Evaluation 5% Parse HTML & CSS 3%
ScriptTotalScriptingParse/CompileParty
Unattributable100ms3ms0ms3rd
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+
JS Bundles
1 scripts, 0 KB unused
PASS
1 scripts, 0 KB unused
0 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.wikimedia.org/portal/wikimedia.org/assets/js/index-56d76e0e59.js4 KB—✓1st
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
s-maxage=3600, must-revalidate, max-age=0
PASS
s-maxage=3600, must-revalidate, max-age=0
Info::
Cache-Control header is set
Got: s-maxage=3600, must-revalidate, max-age=0
Info::
CDN TTL: 1 hour (s-maxage=3600)
Info::
ETag present — enables conditional (304) responses
Info::
Last-Modified header present
Cache-Control

s-maxage=3600, must-revalidate, max-age=0

DirectiveValueMeaning
s-maxage3600CDN caches for 1 hour
must-revalidate—Must recheck with server after expiry
max-age0Cache for 0 seconds
Network Waterfall
21 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
100% of JavaScript execution is third-party
First-party Third-party 100ms · 0KB · $1/mo
Unattributable
Other
Optional
Execution 100ms
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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