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
Compression Algorithm
Main response uses gzip; brotli would be ~20% smaller
REVIEW
Main 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.
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.
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
11 hints, 0 missing preconnects
PASS
11 hints, 0 missing preconnects
Info::
i
2 dns-prefetch redundant with preconnect on same origin
preconnect already does the DNS lookup; adding dns-prefetch to the same origin is at best a no-op. Sample: https://fonts.googleapis.com, https://fonts.gstatic.com. Remove the redundant dns-prefetch entries.
Info::
i
2 URL(s) appear in multiple hints
The same href shouldn't appear in multiple hint rels -- one wins, the others are wasted markup and may confuse cache behavior. Sample: https://fonts.googleapis.com (preconnect+dns-prefetch), https://fonts.gstatic.com (preconnect+dns-prefetch).
Info::
✓
Page uses 11 resource hint(s)
Current Resource Hints
preconnect
5
preload
1
dns-prefetch
5
prefetch—
11 resource hints configured
preconnect already does the DNS lookup; adding dns-prefetch to the same origin is at best a no-op. Sample: https://fonts.googleapis.com, https://fonts.gstatic.com. Remove the redundant dns-prefetch entries.
Why this matters
Performance issues directly impact user engagement and conversion rates.
The same href shouldn't appear in multiple hint rels -- one wins, the others are wasted markup and may confuse cache behavior. Sample: https://fonts.googleapis.com (preconnect+dns-prefetch), https://fonts.gstatic.com (preconnect+dns-prefetch).
Why this matters
Performance issues directly impact user engagement and conversion rates.
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 uses no-cache -- safe revalidate-on-request policy
PASS
Main HTML uses no-cache -- safe revalidate-on-request policy
Info::
✓
Main HTML uses no-cache -- safe revalidate-on-request policy
Got: no-cache, must-revalidate, max-age=0
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: gzip` 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::
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
Network Waterfall
32 requests over 13628ms
INFO
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
33%of JavaScript execution is third-party
First-party Third-party586ms · 395KB · CHF3/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
Google Tag Manager
www.googletagmanager.com
Tag Manager
348ms
161 KB
—
CHF2/mo
Costly
Stripe
js.stripe.com
Payment
238ms
234 KB
—
CHF1/mo
Essential
Google Tag Manager
Tag Manager
Costly
Execution348ms
Transfer161 KB
Monthly CostCHF2/mo
Stripe
Payment
Essential
Execution238ms
Transfer234 KB
Monthly CostCHF1/mo
These scripts may cost more than they're worth
Google Tag Manager adds 348ms and costs ~CHF2/month
Google Tag Manager takes 348ms 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.