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
Document Compression
Document response uses gzip; brotli would be ~20% smaller
REVIEW
Document 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.
C
Asset Compression
Action
1 of 4 asset hosts serve text uncompressed
REVIEW
1 of 4 asset hosts serve text uncompressed
Info::
i
cuatro.sim-cdn.nl serves assets with gzip; brotli would be ~20% smaller (assets: 79)
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: cuatro.sim-cdn.nl (text/css)
Info::
✓
app.tolkie.nl serves assets with brotli (assets: 3)
Got: app.tolkie.nl (text/css)
Info::
i
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)
Warning::
!
woensdrecht.logging.simanalytics.nl serves text assets uncompressed (assets: 3)
The sampled response carries a text content type but no Content-Encoding, so the bytes go over the wire raw. Text compression typically removes 70-80% of a JS or CSS payload -- this is the single cheapest transfer win available on this host.
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 time29 ms
Start956 ms
RiskFOUT — text flashes from fallback to web font
fa-solid-900.woff2woff2swap
Size155 KB
Load time51 ms
Start957 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 time40 ms
Start958 ms
RiskFOUT — text flashes from fallback to web font
open-sans-latin-300-nor...woff2swap
Size19 KB
Load time44 ms
Start958 ms
RiskFOUT — text flashes from fallback to web font
OpenGemeenten.woff2woff2swap
Size26 KB
Load time55 ms
Start958 ms
RiskFOUT — text flashes from fallback to web font
toptaken01.woff2woff2swap
Size10 KB
Load time64 ms
Start959 ms
RiskFOUT — text flashes from fallback to web font
fa-brands-400.woff2woff2swap
Size116 KB
Load time71 ms
Start960 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
x-font-ttf;charset=utf-...unknownswap
Size13 KB
Load time50 ms
Start2.0 s
RiskFOUT — text flashes from fallback to web font
font-woff;charset=utf-8...woffswap
Size25 KB
Load time51 ms
Start2.0 s
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
atkinson-hyperlegible-n...woff2swap
Size13 KB
Load time16 ms
Start2.4 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
10 hints, 0 missing preconnects
PASS
10 hints, 0 missing preconnects
Info::
✓
Page uses 10 resource hint(s)
Current Resource Hints
preconnect—
preload
9
dns-prefetch—
prefetch
1
10 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 7.5 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
72%of JavaScript execution is third-party
First-party Third-party5416ms · 495KB · €59/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
cuatro.sim-cdn.nl
cuatro.sim-cdn.nl
Other
2016ms
63 KB
35%
€22/mo
Costly
woensdrecht.logging.simanalytics.nl
woensdrecht.logging.simanalytics.nl
Other
1328ms
133 KB
44%
€14/mo
Costly
cuatro.sim-cdn.nl
cuatro.sim-cdn.nl
Other
581ms
5 KB
—
€6/mo
Costly
cuatro.sim-cdn.nl
cuatro.sim-cdn.nl
Other
491ms
5 KB
—
€5/mo
Costly
app.tolkie.nl
app.tolkie.nl
Other
443ms
161 KB
—
€5/mo
Costly
cuatro.sim-cdn.nl
cuatro.sim-cdn.nl
Other
214ms
28 KB
—
€2/mo
Costly
woensdrecht.logging.simanalytics.nl
woensdrecht.logging.simanalytics.nl
Other
104ms
35 KB
—
€1/mo
Optional
cdn-eu.readspeaker.com
cdn-eu.readspeaker.com
Other
90ms
28 KB
—
€1/mo
Optional
cuatro.sim-cdn.nl
cuatro.sim-cdn.nl
Other
84ms
27 KB
—
€1/mo
Optional
cuatro.sim-cdn.nl
cuatro.sim-cdn.nl
Other
65ms
10 KB
—
€1/mo
Optional
cuatro.sim-cdn.nl
Other
Costly
Execution2016ms
Transfer63 KB
Unused35%
Monthly Cost€22/mo
woensdrecht.logging.simanalytics.nl
Other
Costly
Execution1328ms
Transfer133 KB
Unused44%
Monthly Cost€14/mo
cuatro.sim-cdn.nl
Other
Costly
Execution581ms
Transfer5 KB
Monthly Cost€6/mo
cuatro.sim-cdn.nl
Other
Costly
Execution491ms
Transfer5 KB
Monthly Cost€5/mo
app.tolkie.nl
Other
Costly
Execution443ms
Transfer161 KB
Monthly Cost€5/mo
cuatro.sim-cdn.nl
Other
Costly
Execution214ms
Transfer28 KB
Monthly Cost€2/mo
woensdrecht.logging.simanalytics.nl
Other
Optional
Execution104ms
Transfer35 KB
Monthly Cost€1/mo
cdn-eu.readspeaker.com
Other
Optional
Execution90ms
Transfer28 KB
Monthly Cost€1/mo
cuatro.sim-cdn.nl
Other
Optional
Execution84ms
Transfer27 KB
Monthly Cost€1/mo
cuatro.sim-cdn.nl
Other
Optional
Execution65ms
Transfer10 KB
Monthly Cost€1/mo
These scripts may cost more than they're worth
cuatro.sim-cdn.nl adds 2016ms and costs ~€22/month
woensdrecht.logging.simanalytics.nl adds 1328ms and costs ~€14/month
cuatro.sim-cdn.nl adds 581ms and costs ~€6/month
cuatro.sim-cdn.nl adds 491ms and costs ~€5/month
app.tolkie.nl adds 443ms and costs ~€5/month
cuatro.sim-cdn.nl adds 214ms and costs ~€2/month
72% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
Why this matters
When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.
Learn more ▾▴
Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.
Source: web.dev
cuatro.sim-cdn.nl takes 2016ms 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
woensdrecht.logging.simanalytics.nl takes 1328ms 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 581ms 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 491ms 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 443ms 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 214ms 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.