Performance

· 21 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.

725 ms

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

1.27 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.

751 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.

1.27 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

12 PASS 6 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.

Image Optimization

4 images, 0 KB saveable

REVIEW

4 images, 0 KB saveable

All images are well-optimized

4 images 53 KB

0 oversized -0 KB

4 legacy format

0 missing dimensions CLS risk

JS Bundles

Action

22 scripts, 196 KB unused

REVIEW

22 scripts, 196 KB unused

https://svennouwen.nl/wp-content/plugins/jupiterx-...: 163 KB unused (86%)

Consider code splitting or tree shaking to reduce unused code.

https://svennouwen.nl/wp-content/themes/jupiterx/l...: 32 KB unused (84%)

Consider code splitting or tree shaking to reduce unused code.

Total unused JavaScript: 196 KB

196 KB unused JavaScript

Downloaded but never executed on this page.

Script	Size	Unused	Minified	Party
https://svennouwen.nl/wp-content/plugins/jupiterx-core/includes/extensions/raven/assets/js/frontend.min.js?ver=7.1	191 KB	163 KB (86%)	✓	1st
https://svennouwen.nl/wp-content/themes/jupiterx/lib/assets/dist/js/frontend.min.js?ver=4.60.0	39 KB	32 KB (84%)	✓	1st
https://svennouwen.nl/wp-includes/js/dist/i18n.min.js?ver=1dfe7db3940c23ea9216	3 KB	—	✓	1st
https://svennouwen.nl/wp-content/plugins/elementor/assets/js/webpack.runtime.min.js?ver=4.2.4	3 KB	—	✓	1st
https://svennouwen.nl/wp-includes/js/dist/hooks.min.js?ver=f0f188028580e8dc1255	2 KB	—	✓	1st
https://svennouwen.nl/wp-content/plugins/elementor/assets/lib/font-awesome/js/v4-shims.min.js?ver=4.2.4	4 KB	—	✓	1st
https://svennouwen.nl/wp-content/plugins/contact-form-7/includes/swv/js/index.js?ver=6.1.7	4 KB	—	✓	1st
https://svennouwen.nl/wp-content/plugins/contact-form-7/includes/js/index.js?ver=6.1.7	4 KB	—	✓	1st
https://svennouwen.nl/wp-content/plugins/jupiterx-core/includes/woocommerce/wc-quick-view.js?ver=4.60.0	1 KB	—	✓	1st
https://svennouwen.nl/wp-includes/js/underscore.min.js?ver=1.13.8	7 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

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.

A+

Page Weight Budget

615 KB transferred, 54 requests

PASS

615 KB transferred, 54 requests

Page weighs 2.7 MB (615 KB transferred)

54 HTTP requests

Estimated 0.13 g CO2 per page load

615 KB transferred

54 requests

0.13 g CO2 per page load

JavaScript 350.8 KiB 57%

CSS 167.2 KiB 27%

Images 52.6 KiB 9%

Fonts 26.7 KiB 4%

HTML 16.8 KiB 3%

Other 1.2 KiB 0%

0 2.4 MB 4.9 MB

Under budget

A+

Third-Party Impact

5% third-party, 0 ms blocking

PASS

5% third-party, 0 ms blocking

Third-party code accounts for 5% of page weight (28.0 KiB of 615.2 KiB)

Third-party blocking time is low (0 ms)

95%

First-party Third-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

277ms total JS execution

PASS

277ms total JS execution

https://svennouwen.nl/: 191ms CPU time

https://svennouwen.nl/wp-includes/js/jquery/jquery...: 86ms CPU time

Main Thread Breakdown

Other 27% Script Evaluation 27% Style & Layout 24% Parse HTML & CSS 9% Rendering 7% Script Parsing & Compilation 6%

Script	Total	Scripting	Parse/Compile	Party
https://svennouwen.nl/	191ms	2ms	1ms	1st
https://svennouwen.nl/wp-includes/js/jquery/jquery.min.js?ver=3.7.1	86ms	63ms	2ms	1st

A+

Font Loading

1 fonts (27 KB)

PASS

1 fonts (27 KB)

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

Web fonts

27 KB total

Render-blocking

of 1

Dominant font-display

swap

Most common across fonts

Font loading timeline

Transfer FOIT (block) FOUT (swap)

LDIoaomQNQcsA88c7O9yZ4K... woff2 swap

Size 27 KB

Load time 41 ms

Start 592 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

A+

Resource Hints

No optimization needed

PASS

No optimization needed

No resource hint issues

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.

A+

Page Weight Inventory

54 resources · 615 KB · 196 KB savings available

PASS

54 resources · 615 KB · 196 KB savings available

Within 1MB page-weight target

Got: 615 KB

~196 KB of savings available

3 third-party resources (5% of weight)

54 resources · 615.2 KiB · 3 third-party Within 1MB page-weight target

JavaScript 57% · 350.8 KiB

CSS 27% · 167.2 KiB

Image 9% · 53.8 KiB

Font 4% · 26.7 KiB

Document 3% · 16.8 KiB

~195.6 KiB of savings available

Remove unused JavaScript: 195.6 KiB

#	Resource	Type	Size	Cache	Unused	3rd party	Issues

54 resources			615.2 KiB

A+

Green Hosting

Whether the site is served from green-energy infrastructure

PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Combell

Network Waterfall

54 requests over 853ms

INFO

HTML JavaScript CSS Images Fonts XHR/Fetch Other

Image Optimization

5 images, 54 KB total, 36 KB wasted

INFO

Image Optimization Audit

Total Images

Total Size

54 KB

Oversized

Wasted

36 KB

3 missing lazy loading

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