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.
B
Page Weight Budget
1.5 MB transferred, 90 requests
REVIEW
1.5 MB transferred, 90 requests
Info::
i
Page weighs 18.4 MB (1.5 MB transferred)
Warning::
!
JavaScript is 945 KB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 945 KB
Info::
i
90 HTTP requests
Info::
i
Estimated 0.31 g CO2 per page load
1.5 MBtransferred
90 requests
0.31 g CO2 per page load
JavaScript944.6 KiB62%
Images427.3 KiB28%
Fonts47.3 KiB3%
Other40.1 KiB3%
Other37.5 KiB2%
CSS19.9 KiB1%
HTML18.8 KiB1%
02.4 MB4.9 MB
Approaching limit
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Why this matters
JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.
Source: web.dev
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
Document Compression
Action
Document response served uncompressed
REVIEW
Document 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
Image Optimization
11 images, 0 KB saveable
PASS
11 images, 0 KB saveable
Warning::
!
https://smartg4.com/airo-assets/images/logo/horizo... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
11images427 KB
0oversized-0 KB
1legacy format
1missing 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
A+
Font Loading
1 fonts (47 KB)
PASS
1 fonts (47 KB)
Info::
i
1 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
1
47 KB total
Render-blocking
0
of 1
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
UcC73FwrK3iLTeHuS_nVMrM...woff2swap
Size47 KB
Load time17 ms
Start672 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
9 hints, 0 missing preconnects
PASS
9 hints, 0 missing preconnects
Info::
i
3 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, https://images.gettyimages.com. Remove the redundant dns-prefetch entries.
Info::
i
3 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), https://images.gettyimages.com (preconnect+dns-prefetch).
Info::
✓
Page uses 9 resource hint(s)
Current Resource Hints
preconnect
3
preload
3
dns-prefetch
3
prefetch—
9 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, https://images.gettyimages.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), https://images.gettyimages.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+
Server Response Intelligence
2 server-response signal(s) detected
PASS
2 server-response signal(s) detected
Info::
✓
`Vary` header declared: Origin
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::
!
Total JS execution time is 6.5 s -- over the 3.5s budget
Total JavaScript execution (parse + compile + run) across all scripts exceeds 3.5 seconds. On low-end devices that becomes 7-15+ seconds and shows up directly in TBT and INP. Reduce by: tree-shaking unused dependencies, code-splitting (dynamic `import()`), removing or deferring third-party tracking, and replacing heavy frameworks where they're not needed.
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
90 requests over 2459ms
INFO
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
61%of JavaScript execution is third-party
First-party Third-party3989ms · 933KB · €21/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
smartg4.com
smartg4.com
Other
1606ms
19 KB
—
€9/mo
Costly
smartg4.com
smartg4.com
Other
1525ms
886 KB
58%
€8/mo
Costly
smartg4.com
smartg4.com
Other
431ms
2 KB
—
€2/mo
Costly
img1.wsimg.com
img1.wsimg.com
Other
259ms
22 KB
—
€1/mo
Costly
smartg4.com
smartg4.com
Other
169ms
4 KB
—
€1/mo
Optional
smartg4.com
Other
Costly
Execution1606ms
Transfer19 KB
Monthly Cost€9/mo
smartg4.com
Other
Costly
Execution1525ms
Transfer886 KB
Unused58%
Monthly Cost€8/mo
smartg4.com
Other
Costly
Execution431ms
Transfer2 KB
Monthly Cost€2/mo
img1.wsimg.com
Other
Costly
Execution259ms
Transfer22 KB
Monthly Cost€1/mo
smartg4.com
Other
Optional
Execution169ms
Transfer4 KB
Monthly Cost€1/mo
These scripts may cost more than they're worth
smartg4.com adds 1606ms and costs ~€9/month
smartg4.com adds 1525ms and costs ~€8/month
smartg4.com adds 431ms and costs ~€2/month
img1.wsimg.com adds 259ms and costs ~€1/month
61% of JavaScript execution time comes from third-party scripts.
Why this matters
Third-party scripts (analytics, ads, social, A/B testing) often dominate execution time — every one is a perf-and-privacy tax.
Learn more ▾▴
Each third-party script is a black box: you don't control when it loads, what it executes, or how much it grows. They often account for a major share of total blocking time on average sites (HTTP Archive's Web Almanac documents the trend). Audit which ones you actually need, defer the rest, and use facade patterns (lite-youtube, lite-vimeo) for embedded media.
Source: web.dev / HTTP Archive Web Almanac
smartg4.com takes 1606ms 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
smartg4.com takes 1525ms 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
58% of smartg4.com's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
smartg4.com takes 431ms 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
img1.wsimg.com takes 259ms 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.