https://lisse.nl
Performance
· 28 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.SCORE
80
GRADE
B
FIX
4
REVIEW
8
PASS
12
INFO
4
Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
67
96
96
100
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
1.45 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
11.02 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
319 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.
3.24 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.
20.23 s
Page Load Progression
Checks
2812 PASS 8 REVIEW 4 FIX
FPage Weight BudgetAction4.4 MB transferred, 75 requestsFIX
Page Weight Budget
Action4.4 MB transferred, 75 requests
4.4 MB transferred, 75 requests
Critical::
Page weighs 6.8 MB (4.4 MB transferred)
Warning::
Images are 2.2 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 2.2 MB
Warning::
JavaScript is 1.9 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.9 MB
Info::
Fonts are 246 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 246 KB
Info::
75 HTTP requests
Info::
Estimated 0.92 g CO2 per page load
4.4 MB transferred
75 requests
0.92 g CO2 per page load
Images 2.2 MiB 49%
JavaScript 1.9 MiB 43%
Fonts 246.5 KiB 6%
CSS 81.2 KiB 2%
HTML 25.5 KiB 1%
Other 3.1 KiB 0%
Other 1.9 KiB 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Over budget
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Why this matters
Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.
Source: web.dev
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Why this matters
JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.
Source: web.dev
Subset fonts to include only used characters, or switch to system font stacks.
Why this matters
Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).
Source: web.dev font loading
DJS BundlesAction15 scripts, 450 KB unusedFIX
JS Bundles
Action15 scripts, 450 KB unused
15 scripts, 450 KB unused
Warning::
https://virtuele-gemeente-assistent.nl/static/js/i...: 377 KB unused (22%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://lisse.nl/wp-content/themes/owc-starter/dis...: 52 KB unused (73%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://lisse.nl/wp/wp-includes/js/jquery/jquery.m...: 21 KB unused (71%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 450 KB
450 KB unused JavaScript
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://virtuele-gemeente-assistent.nl/static/js/ida-widget.js | 1719 KB | 377 KB (22%) | ✓ | 3rd |
| https://lisse.nl/wp-content/themes/owc-starter/dist/client.js?id=bfa6a2af0eb7545537b4abc0f366c9cb&ver=0.1.0 | 71 KB | 52 KB (73%) | ✓ | 1st |
| https://lisse.nl/wp/wp-includes/js/jquery/jquery.min.js?ver=3.7.1 | 30 KB | 21 KB (71%) | ✓ | 1st |
| https://openpub.hltsamen.nl/wp/wp-includes/js/dist/i18n.min.js?ver=c26c3dc7bed366793375 | 2 KB | — | ✓ | 3rd |
| https://lisse.nl/wp-content/plugins/acato-deepl/build/deepl.js?ver=1.5.0 | 6 KB | — | ✓ | 1st |
| https://openpub.hltsamen.nl/wp/wp-includes/js/dist/hooks.min.js?ver=dd5603f07f9220ed27f1 | 2 KB | — | ✓ | 3rd |
| https://lisse.nl/wp-content/plugins/wp-smartcrop/js/jquery.wp-smartcrop.min.js?ver=2.0.10 | 2 KB | — | ✓ | 1st |
| https://meldingen.hollandsmiddenveilig.nl/public/widget/ec4d2a5477bf1445e48f2d43a3e34a57.js | 1 KB | — | ✓ | 3rd |
| https://cdn-eu.readspeaker.com/script/9342/webReader/webReader.js?pids=wr&ver=0.1.0 | 28 KB | — | ✓ | 3rd |
| https://openpub.hltsamen.nl/wp/wp-includes/js/dist/vendor/lodash.min.js?ver=4.17.21 | 25 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
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
FPage Weight InventoryAction75 resources · 4.4 MB · 450 KB savings availableFIX
Page Weight Inventory
Action75 resources · 4.4 MB · 450 KB savings available
75 resources · 4.4 MB · 450 KB savings available
Warning::
Page weight 4.4 MB exceeds 1 MB target by 3.4 MB
Got: 4.4 MB Expected: ≤ 1 MB
Info::
~450 KB of savings available
Warning::
12 third-party resources (41% of weight)
Info::
6 resources over 200KB
75 resources · 4.4 MiB · 12 third-party 3.4 MiB over 1MB target
Image 50% · 2.2 MiB
JavaScript 43% · 1.9 MiB
Font 6% · 246.5 KiB
CSS 2% · 81.2 KiB
Document 1% · 25.5 KiB
Other 0% · 1.9 KiB
~449.8 KiB of savings available
Remove unused JavaScript: 449.8 KiB
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 75 resources | 4.4 MiB | ||||||
DHTTP CachingActionno-store (uncacheable)FIX
HTTP Caching
Actionno-store (uncacheable)
no-store (uncacheable)
Info::
Cache-Control: no-store prevents all caching
Intentional for dynamic content, but increases server load for every page view.
Got: no-store, no-cache, must-revalidate
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control
no-store, no-cache, must-revalidate
| Directive | Value | Meaning |
|---|---|---|
| no-store | — | Never cache this response |
| no-cache | — | Cache but always revalidate first |
| must-revalidate | — | Must recheck with server after expiry |
BThird-Party Impact41% third-party, 0 ms blockingREVIEW
Third-Party Impact
41% third-party, 0 ms blocking
41% third-party, 0 ms blocking
Info::
Third-party code accounts for 41% of page weight (1.8 MiB of 4.4 MiB)
Info::
Third-party blocking time is low (0 ms)
59%
41%
First-party Third-party
BImage Optimization15 images, 0 KB saveableREVIEW
Image Optimization
15 images, 0 KB saveable
15 images, 0 KB saveable
Info::
All images are well-optimized
15 images 2.2 MB
0 oversized -0 KB
13 legacy format
0 missing dimensions CLS risk
CJS Execution CostAction1569ms total JS executionREVIEW
JS Execution Cost
Action1569ms total JS execution
1569ms total JS execution
Warning::
https://virtuele-gemeente-assistent.nl/static/js/i...: 579ms CPU time
Warning::
https://lisse.nl/: 532ms CPU time
Warning::
Unattributable: 286ms CPU time
Info::
https://lisse.nl/wp-content/themes/owc-starter/dis...: 172ms CPU time
Info::
Third-party scripts: 579ms (37% of total)
Main Thread Breakdown
Script Evaluation 32% Style & Layout 22% Other 21% Script Parsing & Compilation 17% Rendering 4% Parse HTML & CSS 4%
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://virtuele-gemeente-assistent.nl/static/js/ida-widget.js | 579ms | 326ms | 252ms | 3rd |
| https://lisse.nl/ | 532ms | 16ms | 7ms | 1st |
| Unattributable | 286ms | 7ms | 0ms | 1st |
| https://lisse.nl/wp-content/themes/owc-starter/dist/client.js?id=bfa6a2af0eb7545537b4abc0f366c9cb&ver=0.1.0 | 172ms | 70ms | 23ms | 1st |
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.
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.
BJavaScript Blocking1 JS blocking issue(s) detectedREVIEW
JavaScript Blocking
1 JS blocking issue(s) detected
1 JS blocking issue(s) detected
Warning::
13 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.
BCSS Performance Depth2 CSS depth issue(s) detectedREVIEW
CSS Performance Depth
2 CSS depth issue(s) detected
2 CSS depth issue(s) detected
Warning::
36 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.
Warning::
1 `@font-face` rule(s) without `font-display` -- causes FOIT
An `@font-face` rule without `font-display` causes Flash of Invisible Text (FOIT): the browser hides the styled text for up to 3 seconds while the custom font downloads, then either swaps to fallback (Chrome / Firefox) or stays invisible (older Safari). Add `font-display: swap` (shows fallback immediately, swaps in the custom font when ready) or `font-display: optional` (uses fallback if the font isn't ready in 100ms; never causes visible swap). Either eliminates FOIT outright.
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.
A+Font Loading4 fonts (246 KB)PASS
Font Loading
4 fonts (246 KB)
4 fonts (246 KB)
Info::
4 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
4
246 KB total
Render-blocking
0
of 4
Dominant font-display
swap
Most common across fonts
Font loading timeline
Transfer FOIT (block) FOUT (swap)
Overpass-Regular.woff2 woff2 swap
Size 60 KB
Load time 100 ms
Start 959 ms
Risk FOUT — text flashes from fallback to web font
Overpass-Medium.woff2 woff2 swap
Size 62 KB
Load time 108 ms
Start 959 ms
Risk FOUT — text flashes from fallback to web font
Overpass-SemiBold.woff2 woff2 swap
Size 62 KB
Load time 100 ms
Start 960 ms
Risk FOUT — text flashes from fallback to web font
Overpass-Bold.woff2 woff2 swap
Size 62 KB
Load time 112 ms
Start 960 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 Hints1 hints, 0 missing preconnectsPASS
Resource Hints
1 hints, 0 missing preconnects
1 hints, 0 missing preconnects
Info::
Page uses 1 resource hint(s)
Current Resource Hints
preconnect—
preload—
dns-prefetch 1
prefetch—
1 resource hints configured
AAsset Compression1 of 1 asset host still on gzipPASS
Asset Compression
1 of 1 asset host still on gzip
1 of 1 asset host still on gzip
Info::
cdn-eu.readspeaker.com serves assets with gzip; brotli would be ~20% smaller (assets: 3)
Every current browser accepts brotli. On a CDN this is a per-pull-zone toggle (Cloudflare, Fastly, CloudFront, CDN77, Bunny all expose it); on an origin it needs the brotli module (nginx-brotli, Apache mod_brotli). The saving lands on the assets this host serves, not on the HTML document -- the document's own encoding is reported separately.
Got: cdn-eu.readspeaker.com (text/css)
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+Main HTML Cache-ControlMain HTML uses no-store -- correct for sensitive/dynamic contentPASS
Main HTML Cache-Control
Main HTML uses no-store -- correct for sensitive/dynamic content
Main HTML uses no-store -- correct for sensitive/dynamic content
Info::
Main HTML uses no-store -- correct for sensitive/dynamic content
Got: no-store, no-cache, must-revalidate
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,User-Agent
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+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
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: Previder BV
Network Waterfall75 requests over 1598msINFO
Network Waterfall
75 requests over 1598ms
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
37% of JavaScript execution is third-party
First-party Third-party 579ms · 1719KB · €6/mo
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
virtuele-gemeente-assistent.nl virtuele-gemeente-assistent.nl | Other | 579ms | 1719 KB | 22% | €6/mo | Costly |
virtuele-gemeente-assistent.nl
Other
Execution 579ms
Transfer 1719 KB
Unused 22%
Monthly Cost €6/mo
These scripts may cost more than they're worth
- virtuele-gemeente-assistent.nl adds 579ms and costs ~€6/month
virtuele-gemeente-assistent.nl takes 579ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Real-User Performance (CrUX)Field metrics from the Chrome User Experience ReportINFO
Real-User Performance (CrUX)
Field metrics from the Chrome User Experience Report
Chrome User Experience (CrUX)
Real-user metrics from the Chrome UX Report (2026-10-14 — 2026-11-10)
LCP (p75)
1621 ms
95% good
INP (p75)
78 ms
96% good
CLS (p75)
0.000
98% good
FCP (p75)
1480 ms
TTFB (p75)
1176 ms
This origin passes Core Web Vitals assessment
Image Optimization15 images, 2262 KB total, 1481 KB wastedINFO
Image Optimization
15 images, 2262 KB total, 1481 KB wasted
Image Optimization Audit
Total Images
15
Total Size
2262 KB
Oversized
7
Wasted
1481 KB
9 missing lazy loading
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.