Performance
· 28 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
2.08 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
19.81 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
263 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.003
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
4.91 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.
21.06 s
Page Load Progression
FPage Weight BudgetAction5.7 MB transferred, 95 requestsFIX
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.
Source: web.dev
CImage OptimizationAction13 images, 0 KB saveableREVIEW
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
CJS Execution CostAction1497ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.medemblik.nl/ | 519ms | 4ms | 1ms | 1st |
| Unattributable | 462ms | 84ms | 0ms | 1st |
| https://www.googletagmanager.com/gtag/js?id=G-F1VSPBF2NY&cx=c>m=4e6ba1 | 203ms | 154ms | 47ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=UA-31146549-1 | 166ms | 116ms | 44ms | 3rd |
| https://cloudstatic.obi4wan.com/ngbots/obi-launcher.bundle.js | 85ms | 50ms | 33ms | 3rd |
| https://www.medemblik.nl/typo3temp/assets/js/e023c9c7c11dc44a842e7cbd1a621020.js?1794364124 | 63ms | 60ms | 0ms | 1st |
CJS BundlesAction20 scripts, 204 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.googletagmanager.com/gtag/js?id=UA-31146549-1 | 133 KB | 71 KB (54%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-F1VSPBF2NY&cx=c>m=4e6ba1 | 167 KB | 69 KB (41%) | ✓ | 3rd |
| https://cloudstatic.obi4wan.com/ngbots/obi-launcher.bundle.js | 107 KB | 64 KB (60%) | ✓ | 3rd |
| https://www.medemblik.nl/typo3temp/assets/js/e023c9c7c11dc44a842e7cbd1a621020.js?1794364124 | 0 KB | — | ✓ | 1st |
| https://www.medemblik.nl/_assets/317130fbcbb12622b6e28e3bfff3cb16/Js/OpenGemeentenSite-Media.min.js?1794359036 | 2 KB | — | ✓ | 1st |
| https://www.medemblik.nl/typo3temp/assets/js/362fa844192ce722db442809b52ebef1.js?1794364124 | 0 KB | — | ✓ | 1st |
| https://www.medemblik.nl/typo3temp/assets/js/7eae658c39bc9c907d0cc72ddadcad26.js?1794364124 | 0 KB | — | ✓ | 1st |
| https://www.medemblik.nl/_assets/6c3bf359f8df9d9222347f37e2814501/JavaScript/OpenGemeentenSiteSearch-PageHeader-Search.min.js?1794359036 | 1 KB | — | ✓ | 1st |
| https://www.medemblik.nl/_assets/6c3bf359f8df9d9222347f37e2814501/JavaScript/OpenGemeentenSiteSearch-Suggest.min.js?1794359036 | 2 KB | — | ✓ | 1st |
| https://www.medemblik.nl/_assets/f52859db1e4f013bae2a279b52772e55/Js/OpenGemeentenCeFeatureCollapsible.min.js?1794359035 | 2 KB | — | ✓ | 1st |
Consider code splitting or tree shaking to reduce unused code.
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.
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.
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
BDocument CompressionDocument response uses gzip; brotli would be ~20% smallerREVIEW
BServer-Timing ObservabilityNo Server-Timing header foundREVIEW
CPage Weight InventoryAction95 resources · 5.7 MB · 204 KB savings availableREVIEW
~204.2 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 95 resources | 5.7 MiB | ||||||
BJavaScript Blocking1 JS blocking issue(s) detectedREVIEW
BHTTP Cachingno-cacheREVIEW
no-cache
| Directive | Value | Meaning |
|---|---|---|
| no-cache | — | Cache but always revalidate first |
A+Third-Party Impact9% third-party, 0 ms blockingPASS
A+Text CompressionAll text resources are compressedPASS
A+Font Loading4 fonts (62 KB)PASS
Web fonts
4
62 KB total
Render-blocking
0
of 4
Dominant font-display
swap
Most common across fonts
Font loading timeline
- Convert to woff2 for ~30% smaller file size
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)
Fixing the unchecked items could save ~11 KB and ~22 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
AAsset Compression1 of 1 asset host still on gzipPASS
A+LCP Image PreloadLCP preload audit not availablePASS
A+Main HTML Cache-ControlMain HTML uses no-cache -- safe revalidate-on-request policyPASS
A+Server Response Intelligence2 server-response signal(s) detectedPASS
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources detectedPASS
ACSS Performance Depth1 CSS depth issue(s) detectedPASS
A+Green HostingWhether the site is served from green-energy infrastructurePASS
Green Hosting
This site is hosted on green energy infrastructure
Provider: Leaseweb Global BV
Network Waterfall95 requests over 932msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
Google Tag Manager www.googletagmanager.com | Tag Manager | 203ms | 167 KB | 41% | €2/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 166ms | 133 KB | 54% | €2/mo | Optional |
cloudstatic.obi4wan.com cloudstatic.obi4wan.com | Other | 85ms | 107 KB | 60% | €1/mo | Optional |
These scripts may cost more than they're worth
- Google Tag Manager adds 203ms and costs ~€2/month
Google Tag Manager takes 203ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
54% of Google Tag Manager's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
60% of cloudstatic.obi4wan.com's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
Real-User Performance (CrUX)Field metrics from the Chrome User Experience ReportINFO
Chrome User Experience (CrUX)
Real-user metrics from the Chrome UX Report (2026-10-14 — 2026-11-10)
LCP (p75)
787 ms
97% good
INP (p75)
71 ms
99% good
CLS (p75)
0.000
97% good
FCP (p75)
761 ms
TTFB (p75)
403 ms
Image Optimization10 images, 1063 KB total, 0 KB wastedINFO
Image Optimization Audit
Total Images
10
Total Size
1063 KB