Performance

· 26 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.

SCORE

GRADE

FIX

REVIEW

PASS

INFO

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop

Performance

Accessibility

100

Best Practices

100

SEO

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

3.62 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

6.78 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

0 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.142

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

3.62 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.

6.78 s

Page Load Progression

375 ms

750 ms

1.1 s

1.5 s

1.9 s

2.2 s

2.6 s

3.0 s

Checks

16 PASS 6 REVIEW 1 FIX

HTTP Caching

Action

no-store (uncacheable)

FIX

no-store (uncacheable)

Cache-Control: no-store prevents all caching

Intentional for dynamic content, but increases server load for every page view.

Got: max-age=0, no-cache, no-store, must-revalidate, private

No ETag or Last-Modified header

Conditional requests (304 Not Modified) are not possible without validators.

Cache-Control

max-age=0, no-cache, no-store, must-revalidate, private

Directive	Value	Meaning
max-age	0	Cache for 0 seconds
no-cache	—	Cache but always revalidate first
no-store	—	Never cache this response
must-revalidate	—	Must recheck with server after expiry
private	—	Only browser cache, not CDN/proxy

Page Weight Budget

1.5 MB transferred, 21 requests

REVIEW

1.5 MB transferred, 21 requests

Page weighs 1.5 MB (1.5 MB transferred)

CSS is 432 KB — consider purging unused styles

Remove unused CSS rules with tools like PurgeCSS to reduce stylesheet size.

Got: 432 KB

21 HTTP requests

Estimated 0.31 g CO2 per page load

1.5 MB transferred

21 requests

0.31 g CO2 per page load

Other 470.5 KiB 31%

Images 470.5 KiB 31%

CSS 431.6 KiB 29%

JavaScript 74.2 KiB 5%

Fonts 47.3 KiB 3%

HTML 4.8 KiB 0%

Other 1.1 KiB 0%

Other 0 B 0%

0 2.4 MB 4.9 MB

Approaching limit

Remove unused CSS rules with tools like PurgeCSS to reduce stylesheet size.

Why this matters

CSS bundle is large — purge unused styles (PurgeCSS, Tailwind JIT) to reduce CSS payload.

Source: web.dev

HTTP/3 (QUIC)

HTTP/3 not advertised

REVIEW

HTTP/3 not advertised

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.

Document Compression

Document response uses gzip; brotli would be ~20% smaller

REVIEW

Document response uses gzip; brotli would be ~20% smaller

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.

Server-Timing Observability

No Server-Timing header found

REVIEW

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.

Page Weight Inventory

Action

21 resources · 1.5 MB · 39 KB savings available

REVIEW

21 resources · 1.5 MB · 39 KB savings available

Page weight 1.5 MB exceeds 1 MB target by 476 KB

Got: 1.5 MB Expected: ≤ 1 MB

5 third-party resources (4% of weight)

3 resources over 200KB

21 resources · 1.5 MiB · 5 third-party 476.1 KiB over 1MB target

Image 63% · 941.1 KiB

CSS 29% · 431.6 KiB

JavaScript 5% · 74.2 KiB

Font 3% · 47.3 KiB

Document 0% · 4.8 KiB

Other 0% · 1.1 KiB

~38.7 KiB of savings available

Remove unused JavaScript: 38.7 KiB

#	Resource	Type	Size	Cache	Unused	3rd party	Issues

21 resources			1.5 MiB

JavaScript Blocking

1 JS blocking issue(s) detected

REVIEW

1 JS blocking issue(s) detected

5 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.

A+

Third-Party Impact

4% third-party, 0 ms blocking

PASS

4% third-party, 0 ms blocking

Third-party code accounts for 4% of page weight (52.5 KiB of 1.5 MiB)

Third-party blocking time is low (0 ms)

96%

First-party Third-party

A+

Text Compression

All text resources are compressed

PASS

All text resources are compressed

All text resources are properly compressed.

A+

Image Optimization

1 images, 0 KB saveable

PASS

1 images, 0 KB saveable

All images are well-optimized

1 images 471 KB

0 oversized -0 KB

1 legacy format

0 missing dimensions CLS risk

A+

JS Execution Cost

452ms total JS execution

PASS

452ms total JS execution

Unattributable: 226ms CPU time

https://brobets.nl/: 226ms CPU time

Main Thread Breakdown

Other 45% Style & Layout 27% Script Evaluation 16% Parse HTML & CSS 7% Rendering 3%

Script	Total	Scripting	Parse/Compile	Party
Unattributable	226ms	7ms	0ms	1st
https://brobets.nl/	226ms	5ms	1ms	1st

A+

Font Loading

1 fonts (47 KB)

PASS

1 fonts (47 KB)

1 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

47 KB total

Render-blocking

of 1

Dominant font-display

swap

Most common across fonts

Font loading timeline

Transfer FOIT (block) FOUT (swap)

UcC73FwrK3iLTeHuS_nVMrM... woff2 swap

Size 47 KB

Load time 110 ms

Start 361 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+

JS Bundles

9 scripts, 39 KB unused

PASS

9 scripts, 39 KB unused

https://brobets.nl/static/js/vendor/htmx-1.9.12.mi...: 39 KB unused (82%)

Consider code splitting or tree shaking to reduce unused code.

Total unused JavaScript: 39 KB

39 KB unused JavaScript

Downloaded but never executed on this page.

Script	Size	Unused	Minified	Party
https://brobets.nl/static/js/vendor/htmx-1.9.12.min.js	47 KB	39 KB (82%)	✓	1st
https://analytics.brobets.nl/script.js	3 KB	—	✓	3rd
https://brobets.nl/static/js/ui/confirm-modal.js?v=20261028-8	8 KB	—	✓	1st
https://brobets.nl/static/js/ui/password-toggle.js	3 KB	—	✓	1st
https://brobets.nl/static/js/ui/prestige-modal.js	2 KB	—	✓	1st
https://brobets.nl/static/js/ui/notif-panel.js	1 KB	—	✓	1st
https://brobets.nl/static/js/ui/info-popup.js	2 KB	—	✓	1st
https://brobets.nl/static/js/refresh.js?v=20261029-1	5 KB	—	✓	1st
https://brobets.nl/static/js/ui/password-toggle.js?v=20261028-2	3 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

A+

Resource Caching

All resources properly cached

PASS

All resources properly cached

No caching issues found

All static resources have appropriate caching headers.

A+

Critical Rendering Path

No render-blocking resources

PASS

No render-blocking resources

No render-blocking resources detected

A+

Resource Hints

No optimization needed

PASS

No optimization needed

No resource hint issues

A+

LCP Image Preload

LCP preload audit not available

PASS

LCP preload audit not available

LCP image preload audit not available for this scan

A+

Main HTML Cache-Control

Main HTML uses no-store -- correct for sensitive/dynamic content

PASS

Main HTML uses no-store -- correct for sensitive/dynamic content

Got: max-age=0, no-cache, no-store, must-revalidate, private

A+

Server Response Intelligence

2 server-response signal(s) detected

PASS

2 server-response signal(s) detected

`Vary` header declared: Cookie

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).

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 Resources

No render-blocking resources detected

PASS

No render-blocking resources detected

No render-blocking resources detected in <head>

A+

Third-Party Resources

No third-party resources detected

PASS

No third-party resources detected

CSS Performance Depth

1 CSS depth issue(s) detected

PASS

1 CSS depth issue(s) detected

6 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 Hosting

Whether the site is served from green-energy infrastructure

PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: OVHcloud

Asset Compression

No text asset hosts to measure

INFO

No text asset hosts to measure

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 Waterfall

21 requests over 679ms

INFO

HTML JavaScript CSS Images Fonts XHR/Fetch Other

Image Optimization

1 images, 470 KB total, 469 KB wasted

INFO

Image Optimization Audit

Total Images

Total Size

470 KB

Oversized

Wasted

469 KB

1 missing dimensions

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.