Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
C
Image Optimization
Action
40 images, 0 KB saveable
REVIEW
40 images, 0 KB saveable
Warning::
!
https://www.swisslux.ch/web/image/779131/trivalite... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/823324/190902_Lo... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/359289/home_logo... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/1114491-bfe4c776... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/997052-f13a7d40/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/832826/Vorlage-I... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/985298-1e5be067/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/836558/12573_kac... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/832828/Internet%... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/786520/Kachelbil... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/823377/190902_Lo... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/857117/13010_kac... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/706118/f1.jpg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/696348/Kachel_72... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/823325/190902_Lo... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/1149455-450b1b0e... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/1043190-2ff200c5... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/689180/02_Bilder... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/725872/Kachel_72... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/689182/02_Bilder... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/350095/home_logo... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/449668/home_logo... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/1177677-badf236f... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/1102958-1813ddb7... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/1027536-c024ce25... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/779133/Kachelbil... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.swisslux.ch/web/image/1050405-d6b461e0... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
40images818 KB
0oversized-0 KB
11legacy format
28missing dimensionsCLS risk
Set explicit width and height to prevent CLS.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
Performance issues directly impact user engagement and conversion rates.
Set explicit width and height to prevent CLS.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
B
Main HTML Cache-Control
No Cache-Control header on main HTML response
REVIEW
No Cache-Control header on main HTML response
Info::
i
Main HTML response has no Cache-Control header
Without an explicit Cache-Control, browsers fall back to heuristic caching (~10% of Last-Modified age). Set `Cache-Control: no-cache` or `max-age=300` for HTML to control freshness explicitly -- prevents stale auth state and SPA shell drift.
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW
Green Hosting
No green hosting detected
A
Third-Party Impact
24% third-party, 0 ms blocking
PASS
24% third-party, 0 ms blocking
Info::
i
Third-party code accounts for 24% of page weight (708.4 KiB of 2.9 MiB)
Info::
✓
Third-party blocking time is low (0 ms)
76%
24%
First-party Third-party
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
4 fonts (174 KB)
PASS
4 fonts (174 KB)
Info::
i
4 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
4
174 KB total
Render-blocking
0
of 4
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
fontawesome-webfont.woff2woff2swap
Size76 KB
Load time79 ms
Start178 ms
RiskFOUT — text flashes from fallback to web font
UcC73FwrK3iLTeHuS_nVMrM...woff2swap
Size47 KB
Load time59 ms
Start421 ms
RiskFOUT — text flashes from fallback to web font
odoo_ui_icons.woff2woff2swap
Size7 KB
Load time35 ms
Start421 ms
RiskFOUT — text flashes from fallback to web font
NGSwv5HMAFg6IuGlBNMjxLs...woff2swap
Size44 KB
Load time61 ms
Start421 ms
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)
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
No optimization needed
PASS
No optimization needed
Info::
✓
No resource hint issues
A+
HTTP/3 (QUIC)
HTTP/3 advertised via Alt-Svc
PASS
HTTP/3 advertised via Alt-Svc
Info::
✓
HTTP/3 (QUIC) is supported
First-load mobile users on cellular networks see meaningful latency improvements with HTTP/3. The QUIC transport collapses TLS + TCP handshakes into one and recovers faster from packet loss.
A+
Document Compression
Document response uses brotli
PASS
Document response uses brotli
Info::
✓
Main HTML response uses brotli (Content-Encoding: br)
Brotli is the best text-compression algorithm for general use, ~20% smaller than gzip on average (40% on smaller files). Modern browsers all support it.
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
A+
Server-Timing Observability
3 Server-Timing entries advertised
PASS
3 Server-Timing entries advertised
Info::
✓
Server-Timing header advertises 3 timing entries
A+
Server Response Intelligence
2 server-response signal(s) detected
PASS
2 server-response signal(s) detected
Info::
✓
`Vary` header declared: accept-encoding
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::
i
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
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::
!
1 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+
CSS Performance Depth
No CSS performance depth issues detected
PASS
No CSS performance depth issues detected
Info::
✓
No CSS performance depth issues detected
Asset Compression
No text asset hosts to measure
INFO
No text asset hosts to measure
Info::
i
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
68 requests over 2046ms
INFO
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
31%of JavaScript execution is third-party
First-party Third-party1030ms · 543KB · CHF16/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
Google Tag Manager
www.googletagmanager.com
Tag Manager
404ms
191 KB
33%
CHF6/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
288ms
189 KB
41%
CHF5/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
252ms
161 KB
41%
CHF4/mo
Costly
Plausible Analytics
plausible.io
Analytics
87ms
2 KB
—
CHF1/mo
Optional
Google Tag Manager
Tag Manager
Costly
Execution404ms
Transfer191 KB
Unused33%
Monthly CostCHF6/mo
Google Tag Manager
Tag Manager
Costly
Execution288ms
Transfer189 KB
Unused41%
Monthly CostCHF5/mo
Google Tag Manager
Tag Manager
Costly
Execution252ms
Transfer161 KB
Unused41%
Monthly CostCHF4/mo
Plausible Analytics
Analytics
Optional
Execution87ms
Transfer2 KB
Monthly CostCHF1/mo
These scripts may cost more than they're worth
Google Tag Manager adds 404ms and costs ~CHF6/month
Google Tag Manager adds 288ms and costs ~CHF5/month
Google Tag Manager adds 252ms and costs ~CHF4/month
Google Tag Manager takes 404ms 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
Google Tag Manager takes 288ms 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
Google Tag Manager takes 252ms 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.
375 ms
2.6 s
3.0 s