Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.

SCORE

GRADE

FIX

REVIEW

PASS

INFO

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

Mobile Desktop

100

Performance

Accessibility

Best Practices

SEO

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

320 ms

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

320 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.

945 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.

320 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

9 PASS 4 REVIEW

Image Optimization

7 images, 0 KB saveable

REVIEW

7 images, 0 KB saveable

All images are well-optimized

7 images 21 KB

0 oversized -0 KB

6 legacy format

0 missing dimensions CLS risk

JS Bundles

5 scripts, 112 KB unused

REVIEW

5 scripts, 112 KB unused

https://osmfoundation.org/w/load.php?lang=en&modul...: 58 KB unused (55%)

Consider code splitting or tree shaking to reduce unused code.

https://osmfoundation.org/w/load.php?lang=en&modul...: 54 KB unused (83%)

Consider code splitting or tree shaking to reduce unused code.

Total unused JavaScript: 112 KB

112 KB unused JavaScript

Downloaded but never executed on this page.

Script	Size	Unused	Minified	Party
https://osmfoundation.org/w/load.php?lang=en&modules=ext.checkUser.clientHints%7Cext.uls.interface%2Cpreferences%2Cwebfonts%7Cjquery%2Coojs%2Csite%7Cjquery.client%2CtextSelection%7Cmediawiki.String%2CTitle%2Capi%2Cbase%2Ccldr%2Ccookie%2Cexperiments%2CjqueryMsg%2Clanguage%2Cstorage%2Cuser%2Cutil%7Cmediawiki.editfont.styles%7Cmediawiki.libs.pluralruleparser%7Cmediawiki.page.ready%7Cmediawiki.page.watch.ajax%7Cskins.vector.clientPreferences%2Cjs%7Cskins.vector.icons.js&skin=vector-2022&version=lvp9h	106 KB	58 KB (55%)	✓	1st
https://osmfoundation.org/w/load.php?lang=en&modules=skins.vector.search.codex.scripts%7Cvue&skin=vector-2022&version=38uqh	65 KB	54 KB (83%)	✓	1st
https://osmfoundation.org/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=vector-2022	12 KB	—	✓	1st
https://osmfoundation.org/w/load.php?lang=en&modules=ext.visualEditor.core.utils.parsing%7Cext.visualEditor.desktopArticleTarget.init%7Cext.visualEditor.progressBarWidget%2CsupportCheck%2CtargetLoader%2CtempWikitextEditorWidget%2Ctrack%2Cve&skin=vector-2022&version=3ti6m	15 KB	—	✓	1st
https://osmfoundation.org/w/load.php?lang=en&modules=ext.uls.webfonts.repository&skin=vector-2022&version=1how9	5 KB	—	✓	1st

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

Green Hosting

Action

Whether the site is served from green-energy infrastructure

REVIEW

Green Hosting

No green hosting detected

HTTP Caching

private, must-revalidate, max-age=0

REVIEW

private, must-revalidate, max-age=0

Cache-Control header is set

Got: private, must-revalidate, max-age=0

Last-Modified header present

Cache-Control

private, must-revalidate, max-age=0

Directive	Value	Meaning
private	—	Only browser cache, not CDN/proxy
must-revalidate	—	Must recheck with server after expiry
max-age	0	Cache for 0 seconds

A+

Page Weight Budget

277 KB transferred, 19 requests

PASS

277 KB transferred, 19 requests

Page weighs 1.0 MB (277 KB transferred)

19 HTTP requests

Estimated 0.06 g CO2 per page load

277 KB transferred

19 requests

0.06 g CO2 per page load

JavaScript 203.9 KiB 74%

Other 24.6 KiB 9%

Images 20.8 KiB 8%

CSS 19.1 KiB 7%

HTML 8.2 KiB 3%

0 2.4 MB 4.9 MB

Under budget

A+

Third-Party Impact

No third-party resources

PASS

No third-party resources

No third-party resources detected

No third-party resources detected — all resources are first-party.

A+

Text Compression

All text resources are compressed

PASS

All text resources are compressed

All text resources are properly compressed.

A+

JS Execution Cost

124ms total JS execution

PASS

124ms total JS execution

https://osmfoundation.org/: 66ms CPU time

Unattributable: 57ms CPU time

Third-party scripts: 57ms (46% of total)

Main Thread Breakdown

Script Evaluation 39% Other 25% Style & Layout 20% Script Parsing & Compilation 9% Rendering 4%

Script	Total	Scripting	Parse/Compile	Party
https://osmfoundation.org/	66ms	2ms	1ms	1st
Unattributable	57ms	2ms	0ms	3rd

A+

Font Loading

No web fonts (system fonts)

PASS

No web fonts (system fonts)

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

No caching issues found

All static resources have appropriate caching headers.

A+

Critical Rendering Path

No render-blocking resources

PASS

No render-blocking resources

No render-blocking resources detected

A+

Resource Hints

No optimization needed

PASS

No optimization needed

No resource hint issues

A+

Page Weight Inventory

19 resources · 277 KB · 112 KB savings available

PASS

19 resources · 277 KB · 112 KB savings available

Within 1MB page-weight target

Got: 277 KB

~112 KB of savings available

2 third-party resources (0% of weight)

19 resources · 276.6 KiB · 2 third-party Within 1MB page-weight target

JavaScript 74% · 203.9 KiB

Document 12% · 32.9 KiB

Image 8% · 20.8 KiB

CSS 7% · 19.1 KiB

~111.6 KiB of savings available

Remove unused JavaScript: 111.6 KiB

#	Resource	Type	Size	Cache	Unused	3rd party	Issues

19 resources			276.6 KiB

Network Waterfall

19 requests over 2789ms

INFO

HTML JavaScript CSS Images Fonts XHR/Fetch Other

Third-Party Script Cost

Per-script blocking time, transfer cost, and cache headers

INFO

46% of JavaScript execution is third-party

First-party Third-party 57ms · 0KB · €1/mo

Script	Category	Execution	Transfer	Unused	Monthly Cost	Verdict
Unattributable Unattributable	Other	57ms	0 KB	—	€1/mo	Optional

Unattributable

Other

Optional

Execution 57ms

Transfer 0 KB

Monthly Cost €1/mo

46% of JavaScript execution time comes from third-party scripts.

Why this matters

Third-party scripts (analytics, ads, social, A/B testing) often dominate execution time — every one is a perf-and-privacy tax.

Learn more ▾

Each third-party script is a black box: you don't control when it loads, what it executes, or how much it grows. They often account for a major share of total blocking time on average sites (HTTP Archive's Web Almanac documents the trend). Audit which ones you actually need, defer the rest, and use facade patterns (lite-youtube, lite-vimeo) for embedded media.

Source: web.dev / HTTP Archive Web Almanac

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.