https://svennouwen.nl
Performance
· 26 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.SCORE
88
GRADE
B
FIX
2
REVIEW
5
PASS
16
INFO
3
Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
85
98
100
100
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
1.83 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.98 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
422 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.
4.65 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.
4.61 s
Page Load Progression
421 ms 841 ms 1.3 s 1.7 s 2.1 s 2.5 s
2.9 s
3.4 sChecks
2616 PASS 5 REVIEW 2 FIX
FJS Execution CostAction3581ms total JS executionFIX
JS Execution Cost
Action3581ms total JS execution
3581ms total JS execution
Warning::
https://svennouwen.nl/: 1707ms CPU time
Warning::
https://svennouwen.nl/wp-content/plugins/elementor...: 756ms CPU time
Warning::
Unattributable: 441ms CPU time
Warning::
https://svennouwen.nl/wp-content/plugins/jupiterx-...: 257ms CPU time
Info::
https://svennouwen.nl/wp-includes/js/jquery/jquery...: 136ms CPU time
Main Thread Breakdown
Script Evaluation 30% Other 28% Style & Layout 23% Script Parsing & Compilation 6% Parse HTML & CSS 6% Rendering 5%
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://svennouwen.nl/ | 1707ms | 46ms | 18ms | 1st |
| https://svennouwen.nl/wp-content/plugins/elementor/assets/js/frontend.min.js?ver=4.3.2 | 756ms | 601ms | 10ms | 1st |
| Unattributable | 441ms | 14ms | 0ms | 1st |
| https://svennouwen.nl/wp-content/plugins/jupiterx-core/includes/extensions/raven/assets/js/frontend.min.js?ver=7.1.2 | 257ms | 127ms | 121ms | 1st |
| https://svennouwen.nl/wp-includes/js/jquery/jquery.min.js?ver=3.7.1 | 136ms | 105ms | 25ms | 1st |
| https://svennouwen.nl/wp-content/themes/jupiterx/lib/assets/dist/js/frontend.min.js?ver=4.61.0 | 116ms | 88ms | 26ms | 1st |
| https://svennouwen.nl/wp-content/plugins/jupiterx-core/includes/extensions/raven/assets/css/frontend.min.css?ver=7.1.2 | 104ms | 0ms | 0ms | 1st |
| https://svennouwen.nl/wp-content/plugins/elementor/assets/js/chunks/text-editor.min.js?ver=4.3.2 | 64ms | 47ms | 5ms | 1st |
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.
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 Budget688 KB transferred, 36 requestsPASS
Page Weight Budget
688 KB transferred, 36 requests
688 KB transferred, 36 requests
Info::
Page weighs 2.6 MB (688 KB transferred)
Info::
36 HTTP requests
Info::
Estimated 0.14 g CO2 per page load
688 KB transferred
36 requests
0.14 g CO2 per page load
JavaScript 353.3 KiB 51%
Images 137.9 KiB 20%
CSS 129.4 KiB 19%
Fonts 48.0 KiB 7%
HTML 17.7 KiB 3%
Other 1.2 KiB 0%
Other 170 B 0%
0 2.4 MB 4.9 MB
Under budget
A+Third-Party ImpactNo third-party resourcesPASS
Third-Party Impact
No third-party resources
No third-party resources
Info::
No third-party resources detected
No third-party resources detected — all resources are first-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 138 KB
0 oversized -0 KB
3 legacy format
0 missing dimensions CLS risk
A+Font Loading4 fonts (48 KB)PASS
Font Loading
4 fonts (48 KB)
4 fonts (48 KB)
Info::
4 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
4
48 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 12 KB
Load time 12 ms
Start 311 ms
Risk FOUT — text flashes from fallback to web font
plus-jakarta-sans-latin... woff2 swap
Size 12 KB
Load time 1.4 s
Start 313 ms
Risk FOUT — text flashes from fallback to web font
plus-jakarta-sans-latin... woff2 swap
Size 12 KB
Load time 195 ms
Start 2.7 s
Risk FOUT — text flashes from fallback to web font
plus-jakarta-sans-latin... woff2 swap
Size 12 KB
Load time 195 ms
Start 2.7 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 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 Hints2 hints, 0 missing preconnectsPASS
Resource Hints
2 hints, 0 missing preconnects
2 hints, 0 missing preconnects
Info::
Page uses 2 resource hint(s)
Current Resource Hints
preconnect—
preload 2
dns-prefetch—
prefetch—
2 resource hints configured
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 Inventory36 resources · 688 KB · 196 KB savings availablePASS
Page Weight Inventory
36 resources · 688 KB · 196 KB savings available
36 resources · 688 KB · 196 KB savings available
Info::
Within 1MB page-weight target
Got: 688 KB
Info::
~196 KB of savings available
36 resources · 687.7 KiB · 0 third-party Within 1MB page-weight target
JavaScript 51% · 353.3 KiB
Image 20% · 139.0 KiB
CSS 19% · 129.4 KiB
Font 7% · 48.0 KiB
Document 3% · 17.7 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 |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 36 resources | 687.7 KiB | ||||||
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
Render-Blocking Resources
No render-blocking resources detected
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+Third-Party ResourcesNo third-party resources detectedPASS
Third-Party Resources
No third-party resources detected
No third-party resources detected
AJavaScript Blocking1 JS blocking issue(s) detectedPASS
JavaScript Blocking
1 JS blocking issue(s) detected
1 JS blocking issue(s) detected
Warning::
Total JS execution time is 3.6 s -- over the 3.5s budget
Total JavaScript execution (parse + compile + run) across all scripts exceeds 3.5 seconds. On low-end devices that becomes 7-15+ seconds and shows up directly in TBT and INP. Reduce by: tree-shaking unused dependencies, code-splitting (dynamic `import()`), removing or deferring third-party tracking, and replacing heavy frameworks where they're not needed.
ACSS Performance Depth1 CSS depth issue(s) detectedPASS
CSS Performance Depth
1 CSS depth issue(s) detected
1 CSS depth issue(s) detected
Warning::
11 render-blocking stylesheet(s) -- recommended: <=3
Each `<link rel="stylesheet">` without a non-blocking `media` attribute holds up the first paint. Browsers download all of them before painting any content. Consolidate into 1-2 critical-path stylesheets; defer non-critical CSS via `<link rel="stylesheet" media="print" onload="this.media='all'">` or via the loadCSS pattern; inline above-the-fold CSS in `<style>` to short-circuit the request entirely.
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 Waterfall36 requests over 3430msINFO
Network Waterfall
36 requests over 3430ms
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.