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.

1.59 s

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

2.01 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.

2.75 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.

2.01 s

Page Load Progression

406 ms

812 ms

1.2 s

1.6 s

2.0 s

2.4 s

2.8 s

3.2 s

Checks

8 PASS 3 REVIEW 2 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 (703.1 KiB of 703.4 KiB)

Third-party blocking time is low (0 ms)

100%

First-party Third-party

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

23 images, 0 KB saveable

REVIEW

23 images, 0 KB saveable

All images are well-optimized

23 images 115 KB

0 oversized -0 KB

22 legacy format

0 missing dimensions CLS risk

JS Bundles

Action

10 scripts, 164 KB unused

REVIEW

10 scripts, 164 KB unused

https://js-eu1.hsforms.net/forms/embed/v2.js: 114 KB unused (61%)

Consider code splitting or tree shaking to reduce unused code.

https://www.strato.de/_assets/main.js: 50 KB unused (61%)

Consider code splitting or tree shaking to reduce unused code.

Total unused JavaScript: 164 KB

164 KB unused JavaScript

Downloaded but never executed on this page.

Script	Size	Unused	Minified	Party
https://js-eu1.hsforms.net/forms/embed/v2.js	195 KB	114 KB (61%)	✓	3rd
https://www.strato.de/_assets/main.js	82 KB	50 KB (61%)	✓	3rd
https://www.strato.de/_assets/setCookie.2e7644a3.js	1 KB	—	✓	3rd
https://widget.trustpilot.com/bootstrap/v5/tp.widget.bootstrap.min.js	8 KB	—	✓	3rd
https://frontend-services.ionos.com/t/tag/STRATO/shop.js	8 KB	—	✓	3rd
https://widget.trustpilot.com/trustboxes/53aa8912dec7e10d38f59f36/main.js	18 KB	—	✓	3rd
https://bbf23v.strato.de/get/live/web/_/963f4q.js	55 KB	—	✓	3rd
https://frontend-services.ionos.com/t/sentry/bundle.min.js	21 KB	—	✓	3rd
https://frontend-services.ionos.com/t/t/js/t.js?v=2.2.1	16 KB	—	✓	3rd
https://frontend-services.ionos.com/t/ias/js/ias.js?v=6.12.19	29 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

Green Hosting

Action

Whether the site is served from green-energy infrastructure

REVIEW

Green Hosting

No green hosting detected

A+

Page Weight Budget

703 KB transferred, 48 requests

PASS

703 KB transferred, 48 requests

Page weighs 2.2 MB (703 KB transferred)

48 HTTP requests

Estimated 0.14 g CO2 per page load

703 KB transferred

48 requests

0.14 g CO2 per page load

JavaScript 433.5 KiB 62%

Images 115.3 KiB 16%

CSS 60.2 KiB 9%

Fonts 34.7 KiB 5%

HTML 29.1 KiB 4%

Other 15.4 KiB 2%

Other 12.9 KiB 2%

Other 2.3 KiB 0%

Other 0 B 0%

0 2.4 MB 4.9 MB

Under budget

A+

Text Compression

All text resources are compressed

PASS

All text resources are compressed

All text resources are properly compressed.

A+

JS Execution Cost

381ms total JS execution

PASS

381ms total JS execution

https://www.strato.de/: 193ms CPU time

Unattributable: 130ms CPU time

https://www.strato.de/_assets/main.js: 58ms CPU time

Third-party scripts: 381ms (100% of total)

Main Thread Breakdown

Other 35% Script Evaluation 26% Style & Layout 23% Script Parsing & Compilation 9% Rendering 5%

Script	Total	Scripting	Parse/Compile	Party
https://www.strato.de/	193ms	4ms	1ms	3rd
Unattributable	130ms	4ms	0ms	3rd
https://www.strato.de/_assets/main.js	58ms	38ms	0ms	3rd

A+

Font Loading

2 fonts (35 KB)

PASS

2 fonts (35 KB)

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

Web fonts

35 KB total

Render-blocking

of 2

Dominant font-display

swap

Most common across fonts

Font loading timeline

Transfer FOIT (block) FOUT (swap)

poppins-v23-latin-regul... woff2 swap

Size 8 KB

Load time 597 ms

Start 1.6 s

Risk FOUT — text flashes from fallback to web font

strato_iconfont.woff2 woff2 swap

Size 27 KB

Load time 785 ms

Start 1.6 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+

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

Page Weight Inventory

48 resources · 703 KB · 164 KB savings available

PASS

48 resources · 703 KB · 164 KB savings available

Within 1MB page-weight target

Got: 703 KB

~164 KB of savings available

47 third-party resources (100% of weight)

48 resources · 703.4 KiB · 47 third-party Within 1MB page-weight target

JavaScript 62% · 433.5 KiB

Image 19% · 130.7 KiB

CSS 9% · 60.2 KiB

Font 5% · 34.7 KiB

Document 4% · 29.4 KiB

Other 2% · 14.8 KiB

~163.8 KiB of savings available

Remove unused JavaScript: 163.8 KiB

#	Resource	Type	Size	Cache	Unused	3rd party	Issues

48 resources			703.4 KiB

Network Waterfall

48 requests over 4151ms

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 381ms · 106KB · €2/mo

Script	Category	Execution	Transfer	Unused	Monthly Cost	Verdict
www.strato.de www.strato.de	Other	193ms	24 KB	—	€1/mo	Optional
Unattributable Unattributable	Other	130ms	0 KB	—	€1/mo	Optional
www.strato.de www.strato.de	Other	58ms	82 KB	61%	€0/mo	Optional

www.strato.de

Other

Optional

Execution 193ms

Transfer 24 KB

Monthly Cost €1/mo

Unattributable

Other

Optional

Execution 130ms

Transfer 0 KB

Monthly Cost €1/mo

www.strato.de

Other

Optional

Execution 58ms

Transfer 82 KB

Unused 61%

Monthly Cost €0/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

61% of www.strato.de'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.