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
35 images, 0 KB saveable
REVIEW
35 images, 0 KB saveable
Warning::
!
https://bureau-savini.be/img/stars/5.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://r2.storagewhise.eu/bureausavini/Pictures/7... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://bureausavini.be/img/avatars/m4.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://bureausavini.be/img/avatars/f2.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://bureau-savini.be/img/ico_google_review.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
35images2.0 MB
0oversized-0 KB
30legacy format
5missing 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
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.
C
Compression Algorithm
Action
Main response served uncompressed
REVIEW
Main response served uncompressed
Info::
i
Main HTML response has no Content-Encoding (uncompressed)
The main HTML document is served without compression. The Text Compression section above lists the broader picture; for the main response specifically, even gzip would shave ~70-80% off most text payloads.
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.
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+
JS Execution Cost
414ms total JS execution
PASS
414ms total JS execution
Warning::
!
https://bureau-savini.be/fr/accueil: 337ms CPU time
Info::
i
Unattributable: 77ms CPU time
Main Thread Breakdown
Style & Layout 36% Other 31% Script Evaluation 15% Rendering 12% Parse HTML & CSS 5%
Script
Total
Scripting
Parse/Compile
Party
https://bureau-savini.be/fr/accueil
337ms
36ms
2ms
1st
Unattributable
77ms
1ms
0ms
1st
A+
Font Loading
6 fonts (503 KB)
PASS
6 fonts (503 KB)
Info::
i
6 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
6
503 KB total
Render-blocking
0
of 6
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
icomoon.ttfttfswap
Size300 KB
Load time111 ms
Start385 ms
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
JTUSjIg1_i6t8kCHKm459Wl...woff2swap
Size35 KB
Load time62 ms
Start387 ms
RiskFOUT — text flashes from fallback to web font
pxiEyp8kv8JHgFVrJJfecnF...woff2swap
Size8 KB
Load time47 ms
Start388 ms
RiskFOUT — text flashes from fallback to web font
pxiByp8kv8JHgFVrLCz7Z1x...woff2swap
Size8 KB
Load time53 ms
Start388 ms
RiskFOUT — text flashes from fallback to web font
bootstrap-icons.woff2woff2swap
Size119 KB
Load time72 ms
Start441 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
KFO7CnqEu92Fr1ME7kSn66a...woff2swap
Size34 KB
Load time103 ms
Start596 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)
Fixing the unchecked items could save ~300 KB and ~600 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
No optimization needed
PASS
No optimization needed
Info::
✓
No resource hint issues
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 Response Intelligence
1 server-response signal(s) detected
PASS
1 server-response signal(s) detected
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.
Network Waterfall
77 requests over 3405ms
INFO
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Image Optimization
61 images, 1005 KB total, 0 KB wasted
INFO
Image Optimization Audit
Total Images
61
Total Size
1005 KB
Oversized
6
37 missing alt text61 missing dimensions60 missing lazy loading
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.