https://svennouwen.nl
Performance
· 22 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.SCORE
87
GRADE
B
FIX
1
REVIEW
6
PASS
12
INFO
3
Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
97
98
92
100
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
749 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.07 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
79 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.001
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
826 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.
1.07 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 sChecks
2212 PASS 6 REVIEW 1 FIX
FHTTP CachingActionNo cache headersFIX
HTTP Caching
ActionNo cache headers
No cache headers
Warning::
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.
BJS Execution Cost994ms total JS executionREVIEW
JS Execution Cost
994ms total JS execution
994ms total JS execution
Warning::
https://svennouwen.nl/: 307ms CPU time
Warning::
https://svennouwen.nl/wp-includes/js/jquery/jquery...: 266ms CPU time
Info::
https://svennouwen.nl/wp-content/themes/jupiterx/l...: 196ms CPU time
Info::
Unattributable: 151ms CPU time
Info::
https://svennouwen.nl/wp-content/plugins/jupiterx-...: 73ms CPU time
Main Thread Breakdown
Script Evaluation 29% Style & Layout 29% Other 25% Script Parsing & Compilation 7% Parse HTML & CSS 6%
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://svennouwen.nl/ | 307ms | 10ms | 5ms | 1st |
| https://svennouwen.nl/wp-includes/js/jquery/jquery.min.js?ver=3.7.1 | 266ms | 197ms | 4ms | 1st |
| https://svennouwen.nl/wp-content/themes/jupiterx/lib/assets/dist/js/frontend.min.js?ver=4.61.0 | 196ms | 12ms | 16ms | 1st |
| Unattributable | 151ms | 3ms | 0ms | 1st |
| https://svennouwen.nl/wp-content/plugins/jupiterx-core/includes/extensions/raven/assets/js/frontend.min.js?ver=7.1.2 | 73ms | 35ms | 31ms | 1st |
CJS BundlesAction15 scripts, 196 KB unusedREVIEW
JS Bundles
Action15 scripts, 196 KB unused
15 scripts, 196 KB unused
Warning::
https://svennouwen.nl/wp-content/plugins/jupiterx-...: 163 KB unused (86%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://svennouwen.nl/wp-content/themes/jupiterx/l...: 32 KB unused (84%)
Consider code splitting or tree shaking to reduce unused code.
Info::
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=7.1.2 | 191 KB | 163 KB (86%) | ✓ | 1st |
| https://svennouwen.nl/wp-content/themes/jupiterx/lib/assets/dist/js/frontend.min.js?ver=4.61.0 | 39 KB | 32 KB (84%) | ✓ | 1st |
| https://svennouwen.nl/wp-content/plugins/elementor/assets/js/frontend-modules.min.js?ver=4.3.2 | 16 KB | — | ✓ | 1st |
| https://svennouwen.nl/wp-includes/js/underscore.min.js?ver=1.13.8 | 7 KB | — | ✓ | 1st |
| https://svennouwen.nl/wp-content/themes/jupiterx/lib/assets/dist/js/utils.min.js?ver=4.61.0 | 0 KB | — | ✓ | 1st |
| https://svennouwen.nl/wp-content/plugins/elementor/assets/js/webpack.runtime.min.js?ver=4.3.2 | 0 KB | — | ✓ | 1st |
| https://svennouwen.nl/wp-includes/js/jquery/jquery.min.js?ver=3.7.1 | 30 KB | — | ✓ | 1st |
| https://svennouwen.nl/wp-includes/js/jquery/ui/core.min.js?ver=1.14.2 | 7 KB | — | ✓ | 1st |
| https://svennouwen.nl/wp-content/plugins/elementor/assets/js/frontend.min.js?ver=4.3.2 | 19 KB | — | ✓ | 1st |
| https://svennouwen.nl/wp-includes/js/wp-util.min.js?ver=7.1.2 | 1 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
BHTTP/3 (QUIC)HTTP/3 not advertisedREVIEW
HTTP/3 (QUIC)
HTTP/3 not advertised
HTTP/3 not advertised
Info::
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.
BDocument CompressionDocument response uses gzip; brotli would be ~20% smallerREVIEW
Document Compression
Document response uses gzip; brotli would be ~20% smaller
Document response uses gzip; brotli would be ~20% smaller
Info::
Main HTML response uses gzip (brotli would be ~20% smaller)
All current browsers support brotli. Most CDNs (Cloudflare, Fastly, AWS CloudFront, Vercel, Netlify) can switch from gzip to brotli with a single config flag. Origin servers (nginx, Apache) need a brotli module compiled in -- nginx-brotli or Apache mod_brotli.
BMain HTML Cache-ControlNo Cache-Control header on main HTML responseREVIEW
Main HTML Cache-Control
No Cache-Control header on main HTML response
No Cache-Control header on main HTML response
Info::
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.
BServer-Timing ObservabilityNo Server-Timing header foundREVIEW
Server-Timing Observability
No Server-Timing header found
No Server-Timing header found
Info::
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 Budget629 KB transferred, 47 requestsPASS
Page Weight Budget
629 KB transferred, 47 requests
629 KB transferred, 47 requests
Info::
Page weighs 2.6 MB (629 KB transferred)
Info::
47 HTTP requests
Info::
Estimated 0.13 g CO2 per page load
629 KB transferred
47 requests
0.13 g CO2 per page load
JavaScript 353.4 KiB 56%
CSS 156.6 KiB 25%
Fonts 50.2 KiB 8%
Images 48.4 KiB 8%
HTML 19.2 KiB 3%
Other 1.2 KiB 0%
Other 170 B 0%
0 2.4 MB 4.9 MB
Under budget
A+Third-Party Impact8% third-party, 0 ms blockingPASS
Third-Party Impact
8% third-party, 0 ms blocking
8% third-party, 0 ms blocking
Info::
Third-party code accounts for 8% of page weight (51.8 KiB of 629.2 KiB)
Info::
Third-party blocking time is low (0 ms)
92%
First-party Third-party
A+Text CompressionAll text resources are compressedPASS
Text Compression
All text resources are compressed
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
AImage Optimization3 images, 0 KB saveablePASS
Image Optimization
3 images, 0 KB saveable
3 images, 0 KB saveable
Info::
All images are well-optimized
3 images 48 KB
0 oversized -0 KB
3 legacy format
0 missing dimensions CLS risk
A+Font Loading4 fonts (50 KB)PASS
Font Loading
4 fonts (50 KB)
4 fonts (50 KB)
Info::
4 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
4
50 KB total
Render-blocking
0
of 4
Dominant font-display
swap
Most common across fonts
Font loading timeline
Transfer FOIT (block) FOUT (swap)
plus-jakarta-sans-latin... woff2 swap
Size 13 KB
Load time 10 ms
Start 826 ms
Risk FOUT — text flashes from fallback to web font
plus-jakarta-sans-latin... woff2 swap
Size 13 KB
Load time 19 ms
Start 827 ms
Risk FOUT — text flashes from fallback to web font
plus-jakarta-sans-latin... woff2 swap
Size 12 KB
Load time 24 ms
Start 827 ms
Risk FOUT — text flashes from fallback to web font
plus-jakarta-sans-latin... woff2 swap
Size 13 KB
Load time 35 ms
Start 828 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 CachingAll resources properly cachedPASS
Resource Caching
All resources properly cached
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+Critical Rendering PathNo render-blocking resourcesPASS
Critical Rendering Path
No render-blocking resources
No render-blocking resources
Info::
No render-blocking resources detected
A+Resource HintsNo optimization neededPASS
Resource Hints
No optimization needed
No optimization needed
Info::
No resource hint issues
A+LCP Image PreloadLCP preload audit not availablePASS
LCP Image Preload
LCP preload audit not available
LCP preload audit not available
Info::
LCP image preload audit not available for this scan
A+Server Response Intelligence2 server-response signal(s) detectedPASS
Server Response Intelligence
2 server-response signal(s) detected
2 server-response signal(s) detected
Info::
`Vary` header declared: Accept-Encoding
The page declares a `Vary` header, telling downstream caches which request headers the response varies on. Critical for content-negotiated responses (compression, language, cookies, device class).
Info::
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 Inventory47 resources · 629 KB · 196 KB savings availablePASS
Page Weight Inventory
47 resources · 629 KB · 196 KB savings available
47 resources · 629 KB · 196 KB savings available
Info::
Within 1MB page-weight target
Got: 629 KB
Info::
~196 KB of savings available
Info::
5 third-party resources (8% of weight)
47 resources · 629.2 KiB · 5 third-party Within 1MB page-weight target
JavaScript 56% · 353.4 KiB
CSS 25% · 156.6 KiB
Font 8% · 50.2 KiB
Image 8% · 49.6 KiB
Document 3% · 19.2 KiB
Other 0% · 170 B
~195.6 KiB of savings available
Remove unused JavaScript: 195.6 KiB
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 47 resources | 629.2 KiB | ||||||
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
Whether the site is served from green-energy infrastructure
Green Hosting
This site is hosted on green energy infrastructure
Provider: Combell
Asset CompressionNo text asset hosts to measureINFO
Asset Compression
No text asset hosts to measure
No text asset hosts to measure
Info::
No third-party or subdomain host served enough text assets to measure
Asset compression is measured per host, from one HEAD request against a sampled resource. Pages that serve all their JS and CSS from the document's own origin are covered by the document compression check instead.
Network Waterfall47 requests over 1363msINFO
Network Waterfall
47 requests over 1363ms
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Image Optimization5 images, 54 KB total, 36 KB wastedINFO
Image Optimization
5 images, 54 KB total, 36 KB wasted
Image Optimization Audit
Total Images
5
Total Size
54 KB
Oversized
2
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.