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
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
B
HTTP/3 (QUIC)
HTTP/3 not advertised
REVIEW
HTTP/3 not advertised
Info::
i
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.
B
Compression Algorithm
Main response uses gzip; brotli would be ~20% smaller
REVIEW
Main response uses gzip; brotli would be ~20% smaller
Info::
i
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.
B
Server-Timing Observability
No Server-Timing header found
REVIEW
No Server-Timing header found
Info::
i
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.
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW
Green Hosting
No green hosting detected
A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
✓
All text resources are compressed
All text resources are properly compressed.
A+
Font Loading
10 fonts (416 KB)
PASS
10 fonts (416 KB)
Info::
i
10 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
10
416 KB total
Render-blocking
0
of 10
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
open-sans-latin-400-nor...woff2swap
Size19 KB
Load time32 ms
Start936 ms
RiskFOUT — text flashes from fallback to web font
fa-solid-900.woff2woff2swap
Size155 KB
Load time47 ms
Start936 ms
RiskFOUT — text flashes from fallback to web font
Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
open-sans-latin-800-nor...woff2swap
Size19 KB
Load time45 ms
Start936 ms
RiskFOUT — text flashes from fallback to web font
open-sans-latin-300-nor...woff2swap
Size19 KB
Load time16 ms
Start1.0 s
RiskFOUT — text flashes from fallback to web font
OpenGemeenten.woff2woff2swap
Size26 KB
Load time20 ms
Start1.0 s
RiskFOUT — text flashes from fallback to web font
toptaken01.woff2woff2swap
Size10 KB
Load time18 ms
Start1.0 s
RiskFOUT — text flashes from fallback to web font
fa-brands-400.woff2woff2swap
Size116 KB
Load time26 ms
Start1.0 s
RiskFOUT — text flashes from fallback to web font
Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
x-font-ttf;charset=utf-...unknownswap
Size13 KB
Load time23 ms
Start2.9 s
RiskFOUT — text flashes from fallback to web font
font-woff;charset=utf-8...woffswap
Size25 KB
Load time24 ms
Start2.9 s
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
atkinson-hyperlegible-n...woff2swap
Size13 KB
Load time647 ms
Start6.0 s
RiskFOUT — 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)
Fixing the unchecked items could save ~147 KB and ~294 ms
A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
✓
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
✓
No render-blocking resources detected
A+
Resource Hints
8 hints, 0 missing preconnects
PASS
8 hints, 0 missing preconnects
Info::
✓
Page uses 8 resource hint(s)
Current Resource Hints
preconnect—
preload
8
dns-prefetch—
prefetch—
8 resource hints configured
A+
LCP Image Preload
LCP preload audit not available
PASS
LCP preload audit not available
Info::
✓
LCP image preload audit not available for this scan
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::
✓
`ETag` present -- conditional GET supported
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
✓
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
A
JavaScript Blocking
1 JS blocking issue(s) detected
PASS
1 JS blocking issue(s) detected
Warning::
!
Total JS execution time is 4.8 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.
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.
Per-script blocking time, transfer cost, and cache headers
INFO
49%of JavaScript execution is third-party
First-party Third-party2350ms · 420KB · €26/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
cuatro.sim-cdn.nl
cuatro.sim-cdn.nl
Other
1205ms
62 KB
35%
€13/mo
Costly
cuatro.sim-cdn.nl
cuatro.sim-cdn.nl
Other
365ms
5 KB
—
€4/mo
Costly
cuatro.sim-cdn.nl
cuatro.sim-cdn.nl
Other
287ms
5 KB
—
€3/mo
Costly
app.tolkie.nl
app.tolkie.nl
Other
202ms
158 KB
—
€2/mo
Costly
cuatro.sim-cdn.nl
cuatro.sim-cdn.nl
Other
139ms
29 KB
—
€2/mo
Optional
woensdrecht.logging.simanalytics.nl
woensdrecht.logging.simanalytics.nl
Other
97ms
133 KB
63%
€1/mo
Optional
cdn-eu.readspeaker.com
cdn-eu.readspeaker.com
Other
54ms
28 KB
—
€1/mo
Optional
cuatro.sim-cdn.nl
Other
Costly
Execution1205ms
Transfer62 KB
Unused35%
Monthly Cost€13/mo
cuatro.sim-cdn.nl
Other
Costly
Execution365ms
Transfer5 KB
Monthly Cost€4/mo
cuatro.sim-cdn.nl
Other
Costly
Execution287ms
Transfer5 KB
Monthly Cost€3/mo
app.tolkie.nl
Other
Costly
Execution202ms
Transfer158 KB
Monthly Cost€2/mo
cuatro.sim-cdn.nl
Other
Optional
Execution139ms
Transfer29 KB
Monthly Cost€2/mo
woensdrecht.logging.simanalytics.nl
Other
Optional
Execution97ms
Transfer133 KB
Unused63%
Monthly Cost€1/mo
cdn-eu.readspeaker.com
Other
Optional
Execution54ms
Transfer28 KB
Monthly Cost€1/mo
These scripts may cost more than they're worth
cuatro.sim-cdn.nl adds 1205ms and costs ~€13/month
cuatro.sim-cdn.nl adds 365ms and costs ~€4/month
cuatro.sim-cdn.nl adds 287ms and costs ~€3/month
app.tolkie.nl adds 202ms and costs ~€2/month
49% of JavaScript execution time comes from third-party scripts.
Why this matters
Third-party scripts (analytics, ads, social, A/B testing) often dominate execution time — every one is a perf-and-privacy tax.
Learn more ▾▴
Each third-party script is a black box: you don't control when it loads, what it executes, or how much it grows. They often account for a major share of total blocking time on average sites (HTTP Archive's Web Almanac documents the trend). Audit which ones you actually need, defer the rest, and use facade patterns (lite-youtube, lite-vimeo) for embedded media.
Source: web.dev / HTTP Archive Web Almanac
cuatro.sim-cdn.nl takes 1205ms 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
cuatro.sim-cdn.nl takes 365ms 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
cuatro.sim-cdn.nl takes 287ms 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
app.tolkie.nl takes 202ms 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
63% of woensdrecht.logging.simanalytics.nl's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.