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

Performance

Accessibility

100

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.

1.09 s

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

1.09 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.

1.09 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.

1.09 s

Page Load Progression

469 ms

938 ms

1.4 s

1.9 s

2.3 s

2.8 s

3.3 s

3.8 s

Checks

8 PASS 4 REVIEW 1 FIX

Third-Party Impact

Action

100% third-party, 0 ms blocking

FIX

100% third-party, 0 ms blocking

Third-party code accounts for 100% of page weight (1.2 MiB of 1.2 MiB)

Third-party blocking time is low (0 ms)

100%

First-party Third-party

Page Weight Budget

1.2 MB transferred, 28 requests

REVIEW

1.2 MB transferred, 28 requests

Page weighs 1.4 MB (1.2 MB transferred)

28 HTTP requests

Estimated 0.25 g CO2 per page load

1.2 MB transferred

28 requests

0.25 g CO2 per page load

Images 921.8 KiB 77%

Fonts 130.2 KiB 11%

JavaScript 84.0 KiB 7%

CSS 32.0 KiB 3%

Other 15.5 KiB 1%

HTML 13.4 KiB 1%

Other 273 B 0%

0 2.4 MB 4.9 MB

Under budget

Image Optimization

10 images, 0 KB saveable

REVIEW

10 images, 0 KB saveable

All images are well-optimized

10 images 922 KB

0 oversized -0 KB

7 legacy format

0 missing dimensions CLS risk

Page Weight Inventory

28 resources · 1.2 MB · 38 KB savings available

REVIEW

28 resources · 1.2 MB · 38 KB savings available

Page weight 173 KB over 1MB target

Got: 1.2 MB Expected: ≤ 1 MB

27 third-party resources (100% of weight)

2 resources over 200KB

28 resources · 1.2 MiB · 27 third-party 173.1 KiB over 1MB target

Image 78% · 936.9 KiB

Font 11% · 130.2 KiB

JavaScript 7% · 84.0 KiB

CSS 3% · 32.0 KiB

Document 1% · 13.8 KiB

Other 0% · 273 B

~37.6 KiB of savings available

Remove unused JavaScript: 37.6 KiB

#	Resource	Type	Size	Cache	Unused	3rd party	Issues

28 resources			1.2 MiB

Green Hosting

Action

Whether the site is served from green-energy infrastructure

REVIEW

Green Hosting

No green hosting detected

A+

Text Compression

All text resources are compressed

PASS

All text resources are compressed

All text resources are properly compressed.

A+

JS Execution Cost

446ms total JS execution

PASS

446ms total JS execution

https://www.virtualmin.com/: 373ms CPU time

Unattributable: 74ms CPU time

Third-party scripts: 446ms (100% of total)

Main Thread Breakdown

Other 48% Style & Layout 33% Script Evaluation 10% Rendering 6%

Script	Total	Scripting	Parse/Compile	Party
https://www.virtualmin.com/	373ms	21ms	3ms	3rd
Unattributable	74ms	3ms	0ms	3rd

A+

Font Loading

4 fonts (130 KB)

PASS

4 fonts (130 KB)

4 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

130 KB total

Render-blocking

of 4

Dominant font-display

swap

Most common across fonts

Font loading timeline

Transfer FOIT (block) FOUT (swap)

font-woff2;charset=utf-... woff2 swap

Size 8 KB

Load time 79 ms

Start 596 ms

Risk FOUT — text flashes from fallback to web font

KFO7CnqEu92Fr1ME7kSn66a... woff2 swap

Size 37 KB

Load time 8 ms

Start 646 ms

Risk FOUT — text flashes from fallback to web font

ieVl2ZhZI2eCN5jzbjEETS9... woff2 swap

Size 45 KB

Load time 8 ms

Start 646 ms

Risk FOUT — text flashes from fallback to web font

KFO5CnqEu92Fr1Mu53ZEC9_... woff2 swap

Size 41 KB

Load time 6 ms

Start 2.7 s

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+

JS Bundles

6 scripts, 38 KB unused

PASS

6 scripts, 38 KB unused

https://stats.virtualmin.com/matomo.js: 38 KB unused (57%)

Consider code splitting or tree shaking to reduce unused code.

Total unused JavaScript: 38 KB

38 KB unused JavaScript

Downloaded but never executed on this page.

Script	Size	Unused	Minified	Party
https://stats.virtualmin.com/matomo.js	67 KB	38 KB (57%)	✓	3rd
https://www.virtualmin.com/assets/js/chocolat.min.62f7175be65b562305f5293096ae0d42280ceae9b387276b8bd1194cc6c20bae.js	9 KB	—	✓	3rd
https://www.virtualmin.com/assets/js/extended/header.min.70fc2045ffb4a59e567ff7ebd46fb283df82434ea67f1e38e0902f0727434b8f.js	1 KB	—	✓	3rd
https://www.virtualmin.com/assets/js/extended/header-chocolat-index.min.bcdde781c845417beeb11f99d794732366722d9c48a91f27286c1d6a95b05869.js	2 KB	—	✓	3rd
https://www.virtualmin.com/assets/js/extended/footer.min.c26ce824391e75610408b9129340d7ad9c87eb71f059393036cbb75d9174e5e9.js	3 KB	—	✓	3rd
https://www.virtualmin.com/assets/js/extended/footer_.min.6b10f939826b76b5279c55bd3517d30b25e2204bf80705ca3a6cf6612966921d.js	1 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

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+

HTTP Caching

max-age=900 (15 minutes)

PASS

max-age=900 (15 minutes)

Cache-Control header is set

Got: public, max-age=900, s-maxage=86400, no-transform, stale-while-revalidate=60, stale-if-error=600

Effective TTL: 15 minutes (max-age=900)

CDN TTL: 1 day (s-maxage=86400)

No ETag or Last-Modified header

Conditional requests (304 Not Modified) are not possible without validators.

Cache-Control

public, max-age=900, s-maxage=86400, no-transform, stale-while-revalidate=60, stale-if-error=600

Directive	Value	Meaning
public	—	Any cache may store this response
max-age	900	Cache for 15 minutes
s-maxage	86400	CDN caches for 1 day
no-transform	—
stale-while-revalidate	60	Serve stale for 1 minute while fetching fresh
stale-if-error	600

Effective TTL: 900 seconds

Network Waterfall

28 requests over 2681ms

INFO

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 446ms · 13KB · €7/mo

Script	Category	Execution	Transfer	Unused	Monthly Cost	Verdict
www.virtualmin.com www.virtualmin.com	Other	373ms	13 KB	—	€6/mo	Costly
Unattributable Unattributable	Other	74ms	0 KB	—	€1/mo	Optional

www.virtualmin.com

Other

Costly

Execution 373ms

Transfer 13 KB

Monthly Cost €6/mo

Unattributable

Other

Optional

Execution 74ms

Transfer 0 KB

Monthly Cost €1/mo

These scripts may cost more than they're worth

www.virtualmin.com adds 373ms and costs ~€6/month

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

www.virtualmin.com takes 373ms 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

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.