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
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
Third-party code accounts for 7% of page weight (492.9 KiB of 7.0 MiB)
Info::
✓
Third-party blocking time is low (0 ms)
93%
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
2 fonts (85 KB)
PASS
2 fonts (85 KB)
Info::
i
2 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
2
85 KB total
Render-blocking
0
of 2
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
UcC73FwrK3iLTeHuS_nVMrM...woff2swap
Size47 KB
Load time48 ms
Start350 ms
RiskFOUT — text flashes from fallback to web font
nuFiD-vYSZviVYUb_rj3ij_...woff2swap
Size38 KB
Load time38 ms
Start351 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+
Compression Algorithm
Main response uses brotli
PASS
Main 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+
Main HTML Cache-Control
Main HTML max-age=0 (≤ 5min) is appropriate
PASS
Main HTML max-age=0 (≤ 5min) is appropriate
Info::
✓
Main HTML max-age=0 (≤ 5min) is appropriate
Got: public, max-age=0, must-revalidate
A
Server Response Intelligence
2 server-response signal(s) detected
PASS
2 server-response signal(s) detected
Warning::
!
Compressed response missing `Vary` header
The page is served with `Content-Encoding: br` but has no `Vary` header. Without `Vary: Accept-Encoding`, intermediary caches (corporate proxies, ISP caches) may serve the compressed variant to clients that didn't send the matching `Accept-Encoding` -- the client sees garbled bytes. Add `Vary: Accept-Encoding` whenever the response is conditionally compressed.
Info::
✓
Both `ETag` and `Last-Modified` present -- efficient revalidation supported
The page returns both `ETag` (content hash) and `Last-Modified` (timestamp) headers. Browsers can issue conditional GETs with `If-None-Match` or `If-Modified-Since`; the server returns 304 Not Modified for unchanged content, saving bandwidth. ETag is the more reliable of the two (timestamps fail in DST transitions and clock skew).
Network Waterfall
33 requests over 917ms
INFO
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Image Optimization
10 images, 15910 KB total, 5814 KB wasted
INFO
Image Optimization Audit
Total Images
10
Total Size
15910 KB
Oversized
8
Wasted
5814 KB
10 missing dimensions8 missing lazy loading
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.