Performance

· 27 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

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.

3.92 s

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

4.21 s

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

12 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.

4.89 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.

4.21 s

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 PASS 8 REVIEW 1 FIX

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.

Third-Party Impact

40% third-party, 0 ms blocking

REVIEW

40% third-party, 0 ms blocking

Third-party code accounts for 40% of page weight (164.7 KiB of 408.6 KiB)

Third-party blocking time is low (0 ms)

60%

40%

First-party Third-party

JS Execution Cost

640ms total JS execution

REVIEW

640ms total JS execution

https://cmp-cdn.golem.de/Notice.b4712.js: 185ms CPU time

https://cmp-cdn.golem.de/wrapperMessagingWithoutDe...: 156ms CPU time

https://www.golem.de/sonstiges/zustimmung/auswahl....: 153ms CPU time

Unattributable: 146ms CPU time

Third-party scripts: 488ms (76% of total)

Main Thread Breakdown

Script Evaluation 47% Other 24% Style & Layout 16% Script Parsing & Compilation 7%

Script	Total	Scripting	Parse/Compile	Party
https://cmp-cdn.golem.de/Notice.b4712.js	185ms	145ms	25ms	3rd
https://cmp-cdn.golem.de/wrapperMessagingWithoutDetection.js	156ms	122ms	19ms	3rd
https://www.golem.de/sonstiges/zustimmung/auswahl.html?from=https%3A%2F%2Fwww.golem.de%2F	153ms	41ms	3ms	1st
Unattributable	146ms	5ms	0ms	3rd

JS Bundles

4 scripts, 91 KB unused

REVIEW

4 scripts, 91 KB unused

https://cmp-cdn.golem.de/Notice.b4712.js: 67 KB unused (73%)

Consider code splitting or tree shaking to reduce unused code.

https://cmp-cdn.golem.de/wrapperMessagingWithoutDe...: 24 KB unused (48%)

Consider code splitting or tree shaking to reduce unused code.

Total unused JavaScript: 91 KB

91 KB unused JavaScript

Downloaded but never executed on this page.

Script	Size	Unused	Minified	Party
https://cmp-cdn.golem.de/Notice.b4712.js	93 KB	67 KB (73%)	✓	3rd
https://cmp-cdn.golem.de/wrapperMessagingWithoutDetection.js	51 KB	24 KB (48%)	✓	3rd
https://www.golem.de/staticrl/scripts/golem_consent_199-min.js	10 KB	—	✓	1st
https://cmp-cdn.golem.de/polyfills.01516.js	2 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

HTTP/3 (QUIC)

HTTP/3 not advertised

REVIEW

HTTP/3 not advertised

HTTP/3 (QUIC) is not advertised

HTTP/3 isn't advertised via Alt-Svc and the worker didn't negotiate h3. HTTP/3 reduces handshake latency (1-RTT instead of 2-3 RTTs) and is more resilient on lossy connections. Most modern CDNs (Cloudflare, Fastly, AWS CloudFront, Google Cloud CDN) support HTTP/3 with a single config switch -- consider enabling for mobile-heavy workloads.

Compression Algorithm

Action

Main response served uncompressed

REVIEW

Main response served uncompressed

Main HTML response has no Content-Encoding (uncompressed)

The main HTML document is served without compression. The Text Compression section above lists the broader picture; for the main response specifically, even gzip would shave ~70-80% off most text payloads.

Main HTML Cache-Control

No Cache-Control header on main HTML response

REVIEW

No Cache-Control header on main HTML response

Main HTML response has no Cache-Control header

Without an explicit Cache-Control, browsers fall back to heuristic caching (~10% of Last-Modified age). Set `Cache-Control: no-cache` or `max-age=300` for HTML to control freshness explicitly -- prevents stale auth state and SPA shell drift.

Server-Timing Observability

No Server-Timing header found

REVIEW

No Server-Timing header found

Server-Timing exposes backend timing breakdowns to browser DevTools (e.g., `db: 45ms; render: 120ms; cache: 2ms`). Useful for diagnosing slow pages without backend log access. Most modern frameworks (Next.js, Cloudflare Workers, Fastly) emit it automatically; absence on a managed platform usually means telemetry headers are stripped at the edge.

Green Hosting

Action

Whether the site is served from green-energy infrastructure

REVIEW

Green Hosting

No green hosting detected

A+

Page Weight Budget

409 KB transferred, 23 requests

PASS

409 KB transferred, 23 requests

Page weighs 976 KB (409 KB transferred)

23 HTTP requests

Estimated 0.08 g CO2 per page load

409 KB transferred

23 requests

0.08 g CO2 per page load

JavaScript 155.9 KiB 38%

CSS 90.1 KiB 22%

Fonts 69.7 KiB 17%

Other 37.7 KiB 9%

Images 24.5 KiB 6%

HTML 20.6 KiB 5%

Other 10.1 KiB 2%

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.

Image Optimization

3 images, 0 KB saveable

PASS

3 images, 0 KB saveable

https://www.golem.de/staticrl/images/Golem-Logo-wh... is missing width/height — may cause layout shift

Set explicit width and height to prevent CLS.

3 images 24 KB

0 oversized -0 KB

2 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

A+

Font Loading

2 fonts (70 KB)

PASS

2 fonts (70 KB)

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

Web fonts

70 KB total

Render-blocking

of 2

Dominant font-display

swap

Most common across fonts

Font loading timeline

Transfer FOIT (block) FOUT (swap)

SpaceGrotesk-variable.w... woff2 swap

Size 48 KB

Load time 98 ms

Start 156 ms

Risk FOUT — text flashes from fallback to web font

DroidSans.woff2 woff2 swap

Size 21 KB

Load time 165 ms

Start 903 ms

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

Resource Hints

3 hints, 0 missing preconnects

PASS

3 hints, 0 missing preconnects

1 dns-prefetch redundant with preconnect on same origin

preconnect already does the DNS lookup; adding dns-prefetch to the same origin is at best a no-op. Sample: https://cmp-cdn.golem.de. Remove the redundant dns-prefetch entries.

1 URL(s) appear in multiple hints

The same href shouldn't appear in multiple hint rels -- one wins, the others are wasted markup and may confuse cache behavior. Sample: //cmp-cdn.golem.de (dns-prefetch+preconnect).

Page uses 3 resource hint(s)

Current Resource Hints

preconnect

preload

dns-prefetch

prefetch

—

3 resource hints configured

preconnect already does the DNS lookup; adding dns-prefetch to the same origin is at best a no-op. Sample: https://cmp-cdn.golem.de. Remove the redundant dns-prefetch entries.

Why this matters

Performance issues directly impact user engagement and conversion rates.

The same href shouldn't appear in multiple hint rels -- one wins, the others are wasted markup and may confuse cache behavior. Sample: //cmp-cdn.golem.de (dns-prefetch+preconnect).

Why this matters

Performance issues directly impact user engagement and conversion rates.

A+

LCP Image Preload

LCP preload audit not available

PASS

LCP preload audit not available

LCP image preload audit not available for this scan

A+

Server Response Intelligence

1 server-response signal(s) detected

PASS

1 server-response signal(s) detected

No `ETag` or `Last-Modified` -- conditional GET not supported

Without either header, browsers can't issue conditional GETs and refresh always re-downloads the full response body even when nothing changed. Add `ETag: "<hash>"` (or `Last-Modified: <date>`) on cacheable responses; the server returns 304 Not Modified when the client's cached copy is still valid, saving bandwidth.

Page Weight Inventory

23 resources · 409 KB · 91 KB savings available

PASS

23 resources · 409 KB · 91 KB savings available

Within 1MB page-weight target

Got: 409 KB

~91 KB of savings available

13 third-party resources (40% of weight)

23 resources · 408.6 KiB · 13 third-party Within 1MB page-weight target

JavaScript 38% · 155.9 KiB

CSS 22% · 90.1 KiB

Font 17% · 69.7 KiB

Image 15% · 61.9 KiB

Document 5% · 21.2 KiB

Other 2% · 9.8 KiB

~91.5 KiB of savings available

Remove unused JavaScript: 91.5 KiB

#	Resource	Type	Size	Cache	Unused	3rd party	Issues

23 resources			408.6 KiB

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

JavaScript Blocking

1 JS blocking issue(s) detected

PASS

1 JS blocking issue(s) detected

1 render-blocking <script src> tag(s) without async/defer

Each `<script src=...>` without `async`, `defer`, or `type="module"` blocks HTML parsing while the browser fetches and executes it. The block lasts the entire round-trip + execution time -- on slow networks this translates directly into LCP delay. Add `defer` (executes after parse, in source order) for scripts that interact with the DOM, or `async` (executes whenever ready) for analytics / independent scripts. Module scripts (`type="module"`) are deferred by default.

A+

CSS Performance Depth

No CSS performance depth issues detected

PASS

No CSS performance depth issues detected

Network Waterfall

23 requests over 1069ms

INFO

HTML JavaScript CSS Images Fonts XHR/Fetch Other

Third-Party Script Cost

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

INFO

76% of JavaScript execution is third-party

First-party Third-party 488ms · 144KB · €5/mo

Script	Category	Execution	Transfer	Unused	Monthly Cost	Verdict
cmp-cdn.golem.de cmp-cdn.golem.de	Other	185ms	93 KB	73%	€2/mo	Optional
cmp-cdn.golem.de cmp-cdn.golem.de	Other	156ms	51 KB	48%	€2/mo	Optional
Unattributable Unattributable	Other	146ms	0 KB	—	€2/mo	Optional

cmp-cdn.golem.de

Other

Optional

Execution 185ms

Transfer 93 KB

Unused 73%

Monthly Cost €2/mo

cmp-cdn.golem.de

Other

Optional

Execution 156ms

Transfer 51 KB

Unused 48%

Monthly Cost €2/mo

Unattributable

Other

Optional

Execution 146ms

Transfer 0 KB

Monthly Cost €2/mo

76% 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

73% of cmp-cdn.golem.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

Real-User Performance (CrUX)

Field metrics from the Chrome User Experience Report

INFO

Chrome User Experience (CrUX)

Real-user metrics from the Chrome UX Report (2026-04-12 — 2026-05-09)

LCP (p75)

919 ms

92% good

INP (p75)

96 ms

93% good

CLS (p75)

0.020

92% good

FCP (p75)

719 ms

TTFB (p75)

264 ms

This origin passes Core Web Vitals assessment

Image Optimization

1 images, 2 KB total, 0 KB wasted

INFO

Image Optimization Audit

Total Images

Total Size

2 KB

1 missing dimensions

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.