Consider code splitting or tree shaking to reduce unused code.
Why this matters
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
Why this matters
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
Consider code splitting or tree shaking to reduce unused code.
Why this matters
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
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.
B
Document Compression
Document response uses gzip; brotli would be ~20% smaller
REVIEW
Document 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
Asset Compression
2 of 3 asset hosts still on gzip
REVIEW
2 of 3 asset hosts still on gzip
Info::
i
iol-website.italiaonline.it serves assets with gzip; brotli would be ~20% smaller (assets: 10)
Every current browser accepts brotli. On a CDN this is a per-pull-zone toggle (Cloudflare, Fastly, CloudFront, CDN77, Bunny all expose it); on an origin it needs the brotli module (nginx-brotli, Apache mod_brotli). The saving lands on the assets this host serves, not on the HTML document -- the document's own encoding is reported separately.
irp.cdn-website.com serves assets with brotli (assets: 10)
Got: irp.cdn-website.com (text/css)
Info::
i
static.cdn-website.com serves assets with gzip; brotli would be ~20% smaller (assets: 3)
Every current browser accepts brotli. On a CDN this is a per-pull-zone toggle (Cloudflare, Fastly, CloudFront, CDN77, Bunny all expose it); on an origin it needs the brotli module (nginx-brotli, Apache mod_brotli). The saving lands on the assets this host serves, not on the HTML document -- the document's own encoding is reported separately.
Got: static.cdn-website.com (text/css)
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.
B
JavaScript Blocking
2 JS blocking issue(s) detected
REVIEW
2 JS blocking issue(s) detected
Warning::
!
7 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.
Warning::
!
Total JS execution time is 4.8 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.
Each `<link rel="stylesheet">` without a non-blocking `media` attribute holds up the first paint. Browsers download all of them before painting any content. Consolidate into 1-2 critical-path stylesheets; defer non-critical CSS via `<link rel="stylesheet" media="print" onload="this.media='all'">` or via the loadCSS pattern; inline above-the-fold CSS in `<style>` to short-circuit the request entirely.
Warning::
!
4 `@font-face` rule(s) without `font-display` -- causes FOIT
An `@font-face` rule without `font-display` causes Flash of Invisible Text (FOIT): the browser hides the styled text for up to 3 seconds while the custom font downloads, then either swaps to fallback (Chrome / Firefox) or stays invisible (older Safari). Add `font-display: swap` (shows fallback immediately, swaps in the custom font when ready) or `font-display: optional` (uses fallback if the font isn't ready in 100ms; never causes visible swap). Either eliminates FOIT outright.
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
JavaScript is 614 KB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 614 KB
Info::
i
79 HTTP requests
Info::
i
Estimated 0.17 g CO2 per page load
826 KBtransferred
79 requests
0.17 g CO2 per page load
JavaScript613.8 KiB74%
Fonts76.4 KiB9%
Images51.7 KiB6%
CSS47.7 KiB6%
HTML28.4 KiB3%
Other4.9 KiB1%
Other1.9 KiB0%
Other1.7 KiB0%
Other0 B0%
02.4 MB4.9 MB
Under budget
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
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
6 fonts (76 KB)
PASS
6 fonts (76 KB)
Info::
i
6 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
6
76 KB total
Render-blocking
0
of 6
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
pxiEyp8kv8JHgFVrJJfecg....woff2swap
Size8 KB
Load time20 ms
Start449 ms
RiskFOUT — text flashes from fallback to web font
pxiByp8kv8JHgFVrLCz7Z1x...woff2swap
Size8 KB
Load time17 ms
Start450 ms
RiskFOUT — text flashes from fallback to web font
pxiByp8kv8JHgFVrLEj6Z1x...woff2swap
Size8 KB
Load time14 ms
Start451 ms
RiskFOUT — text flashes from fallback to web font
O4ZXFGj5hxF0EhjimlIhggo...woff2swap
Size37 KB
Load time24 ms
Start451 ms
RiskFOUT — text flashes from fallback to web font
pxiByp8kv8JHgFVrLDz8Z1x...woff2swap
Size8 KB
Load time21 ms
Start451 ms
RiskFOUT — text flashes from fallback to web font
pxiByp8kv8JHgFVrLGT9Z1x...woff2swap
Size8 KB
Load time7 ms
Start1.1 s
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
3 hints, 0 missing preconnects
PASS
3 hints, 0 missing preconnects
Info::
i
1 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://irp.cdn-website.com (preconnect+preconnect).
Info::
✓
Page uses 3 resource hint(s)
Current Resource Hints
preconnect
3
preload—
dns-prefetch—
prefetch—
3 resource hints configured
The same href shouldn't appear in multiple hint rels -- one wins, the others are wasted markup and may confuse cache behavior. Sample: https://irp.cdn-website.com (preconnect+preconnect).
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
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).
Per-script blocking time, transfer cost, and cache headers
INFO
74%of JavaScript execution is third-party
First-party Third-party3559ms · 478KB · €34/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
iol-website.italiaonline.it
iol-website.italiaonline.it
Other
1814ms
13 KB
—
€18/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
436ms
187 KB
40%
€4/mo
Costly
static.cdn-website.com
static.cdn-website.com
Other
423ms
101 KB
61%
€4/mo
Costly
consent.cookiebot.com
consent.cookiebot.com
Other
412ms
105 KB
24%
€4/mo
Costly
consent.cookiebot.com
consent.cookiebot.com
Other
255ms
37 KB
—
€2/mo
Costly
static.cdn-website.com
static.cdn-website.com
Other
160ms
12 KB
—
€2/mo
Optional
static.cdn-website.com
static.cdn-website.com
Other
58ms
22 KB
—
€1/mo
Optional
iol-website.italiaonline.it
Other
Costly
Execution1814ms
Transfer13 KB
Monthly Cost€18/mo
Google Tag Manager
Tag Manager
Costly
Execution436ms
Transfer187 KB
Unused40%
Monthly Cost€4/mo
static.cdn-website.com
Other
Costly
Execution423ms
Transfer101 KB
Unused61%
Monthly Cost€4/mo
consent.cookiebot.com
Other
Costly
Execution412ms
Transfer105 KB
Unused24%
Monthly Cost€4/mo
consent.cookiebot.com
Other
Costly
Execution255ms
Transfer37 KB
Monthly Cost€2/mo
static.cdn-website.com
Other
Optional
Execution160ms
Transfer12 KB
Monthly Cost€2/mo
static.cdn-website.com
Other
Optional
Execution58ms
Transfer22 KB
Monthly Cost€1/mo
These scripts may cost more than they're worth
iol-website.italiaonline.it adds 1814ms and costs ~€18/month
Google Tag Manager adds 436ms and costs ~€4/month
static.cdn-website.com adds 423ms and costs ~€4/month
consent.cookiebot.com adds 412ms and costs ~€4/month
consent.cookiebot.com adds 255ms and costs ~€2/month
74% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
Why this matters
When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.
Learn more ▾▴
Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.
Source: web.dev
iol-website.italiaonline.it takes 1814ms 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 436ms 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
static.cdn-website.com takes 423ms 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
61% of static.cdn-website.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
consent.cookiebot.com takes 412ms 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
consent.cookiebot.com takes 255ms 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.