Performance

· 17 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

100

SEO

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

3.89 s

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

4.42 s

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

52 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.002

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

5.81 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.

8.37 s

Page Load Progression

556 ms

1.1 s

1.7 s

2.2 s

2.8 s

3.3 s

3.9 s

4.4 s

Checks

7 PASS 4 REVIEW 4 FIX

Page Weight Budget

Action

2.2 MB transferred, 54 requests

FIX

2.2 MB transferred, 54 requests

Page weighs 3.7 MB (2.2 MB transferred)

Images are 1.3 MB — compress or use modern formats

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

Got: 1.3 MB

Fonts are 633 KB — consider subsetting or using system fonts

Subset fonts to include only used characters, or switch to system font stacks.

Got: 633 KB

54 HTTP requests

Estimated 0.47 g CO2 per page load

2.2 MB transferred

54 requests

0.47 g CO2 per page load

Images 1.3 MiB 59%

Fonts 632.6 KiB 28%

CSS 144.1 KiB 6%

JavaScript 105.1 KiB 5%

HTML 53.0 KiB 2%

Other 1.3 KiB 0%

Other 382 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

Subset fonts to include only used characters, or switch to system font stacks.

Why this matters

Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).

Source: web.dev font loading

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 (2.2 MiB of 2.2 MiB)

Third-party blocking time is low (0 ms)

100%

First-party Third-party

Page Weight Inventory

Action

54 resources · 2.2 MB · 38 KB savings available

FIX

54 resources · 2.2 MB · 38 KB savings available

Page weight 1.2 MB over 1MB target

Got: 2.2 MB Expected: ≤ 1 MB

53 third-party resources (100% of weight)

3 resources over 200KB

54 resources · 2.2 MiB · 53 third-party 1.2 MiB over 1MB target

Image 59% · 1.3 MiB

Font 28% · 632.6 KiB

CSS 6% · 144.1 KiB

JavaScript 5% · 105.1 KiB

Document 2% · 53.5 KiB

~37.9 KiB of savings available

Remove unused JavaScript: 37.9 KiB

#	Resource	Type	Size	Cache	Unused	3rd party	Issues

54 resources			2.2 MiB

HTTP Caching

Action

No cache headers

FIX

No cache headers

No Cache-Control header found

Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

Image Optimization

13 images, 0 KB saveable

REVIEW

13 images, 0 KB saveable

https://www.fau.de/wp-content/themes/FAU-Elemental... is missing width/height — may cause layout shift

Set explicit width and height to prevent CLS.

13 images 1.3 MB

0 oversized -0 KB

9 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

JS Execution Cost

Action

1587ms total JS execution

REVIEW

1587ms total JS execution

https://www.fau.de/: 1002ms CPU time

Unattributable: 361ms CPU time

https://www.fau.de/wp-includes/js/jquery/jquery.js...: 224ms CPU time

Third-party scripts: 1587ms (100% of total)

Main Thread Breakdown

Style & Layout 40% Other 29% Script Evaluation 11% Parse HTML & CSS 11% Rendering 7% Script Parsing & Compilation 3%

Script	Total	Scripting	Parse/Compile	Party
https://www.fau.de/	1002ms	22ms	5ms	3rd
Unattributable	361ms	7ms	0ms	3rd
https://www.fau.de/wp-includes/js/jquery/jquery.js?ver=3.7.1	224ms	101ms	38ms	3rd

JS Bundles

9 scripts, 38 KB unused

REVIEW

9 scripts, 38 KB unused

https://www.fau.de/wp-includes/js/jquery/jquery.js...: 38 KB unused (46%)

Consider code splitting or tree shaking to reduce unused code.

https://www.fau.de/wp-includes/js/jquery/jquery.js...: unminified — 42 KB could be saved

https://www.fau.de/wp-includes/js/jquery/jquery-mi...: unminified — 4 KB could be saved

Total unused JavaScript: 38 KB

38 KB unused JavaScript

Downloaded but never executed on this page.

Script	Size	Unused	Minified	Party
https://www.fau.de/wp-includes/js/jquery/jquery.js?ver=3.7.1	82 KB	38 KB (46%)	✗	3rd
https://www.fau.de/wp-includes/js/jquery/jquery-migrate.js?ver=3.4.1	10 KB	—	✗	3rd
https://www.fau.de/wp-content/plugins/fau-orga-breadcrumb/build/modal-cleanup.js?ver=11bc024679ba054b0110	0 KB	—	✓	3rd
https://www.fau.de/wp-content/themes/FAU-Elemental/build/blocks/fau-teaser-grid/view.js?ver=09785b64fa9a6fca12e4	1 KB	—	✓	3rd
https://www.fau.de/wp-content/themes/FAU-Elemental/build/blocks/fau-testimonial/view.js?ver=83e6ffce473015895fbd	0 KB	—	✓	3rd
https://www.fau.de/wp-content/themes/FAU-Elemental/build/js/menu-modal.js?ver=b96b0ea7763075f2ca77	4 KB	—	✓	3rd
https://www.fau.de/wp-content/themes/FAU-Elemental/build/js/social-media-icons.js?ver=311a89a03d6770acb643	0 KB	—	✓	3rd
https://www.fau.de/wp-content/plugins/rrze-legal/build/banner.js?ver=2.8.9	6 KB	—	✓	3rd
https://www.fau.de/wp-content/plugins/rrze-calendar/build/block/view.js?ver=31d6cfe0d16ae931b73c	0 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

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+

Font Loading

1 fonts (633 KB)

PASS

1 fonts (633 KB)

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

Web fonts

633 KB total

Render-blocking

of 1

Dominant font-display

swap

Most common across fonts

Font loading timeline

Transfer FOIT (block) FOUT (swap)

SourceSans3-VariableFon... ttf swap

Size 633 KB

Load time 416 ms

Start 2.2 s

Risk FOUT — text flashes from fallback to web font

Convert to woff2 for ~30% smaller file size
Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need

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)

Fixing the unchecked items could save ~506 KB and ~1012 ms

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+

Render-Blocking Resources

No render-blocking resources detected

PASS

No render-blocking resources detected

No render-blocking resources detected in <head>

A+

Third-Party Resources

No third-party resources detected

PASS

No third-party resources detected

Network Waterfall

54 requests over 4274ms

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 1587ms · 135KB · €17/mo

Script	Category	Execution	Transfer	Unused	Monthly Cost	Verdict
www.fau.de www.fau.de	Other	1002ms	53 KB	—	€11/mo	Costly
Unattributable Unattributable	Other	361ms	0 KB	—	€4/mo	Costly
www.fau.de www.fau.de	Other	224ms	82 KB	46%	€2/mo	Costly

www.fau.de

Other

Costly

Execution 1002ms

Transfer 53 KB

Monthly Cost €11/mo

Unattributable

Other

Costly

Execution 361ms

Transfer 0 KB

Monthly Cost €4/mo

www.fau.de

Other

Costly

Execution 224ms

Transfer 82 KB

Unused 46%

Monthly Cost €2/mo

These scripts may cost more than they're worth

www.fau.de adds 1002ms and costs ~€11/month
Unattributable adds 361ms and costs ~€4/month
www.fau.de adds 224ms and costs ~€2/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.fau.de takes 1002ms 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

Unattributable takes 361ms 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

www.fau.de takes 224ms 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.