Performance
· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.Performance-focused optimization plan with CWV assessment, top offenders, and time estimates
First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.
1.07 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
3.20 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
107 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.005
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
2.16 s
Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.
3.20 s
Page Load Progression
FPage Weight BudgetAction2.8 MB transferred, 182 requestsFIX
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.
Source: web.dev
Subset fonts to include only used characters, or switch to system font stacks.
Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).
Source: web.dev font loading
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.
Source: web.dev
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
FJS BundlesAction121 scripts, 449 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.sky.it/_next/static/chunks/pages/_app-71ef376c6516b45f.js | 175 KB | 109 KB (62%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-RWMN51KW03 | 176 KB | 64 KB (37%) | ✓ | 3rd |
| https://cmp.sky.it/Notice.8f529.js | 91 KB | 61 KB (67%) | ✓ | 3rd |
| https://ctlive.sky.it/livechat/SKY/amdlib/jquery-ui-dist/jquery-ui.min.js?define=__ctliveDefine | 67 KB | 59 KB (89%) | ✓ | 3rd |
| https://ctlive.sky.it/livechat/SKY/widget/widget.js | 63 KB | 58 KB (93%) | ✗ | 3rd |
| https://www.datadoghq-browser-agent.com/eu1/v6/datadog-rum.js | 58 KB | 31 KB (53%) | ✓ | 3rd |
| https://cdn.privacy-mgmt.com/wrapperMessagingWithoutDetection.js | 54 KB | 23 KB (44%) | ✓ | 3rd |
| https://www.sky.it/_next/static/chunks/framework-35048067b0fccd1f.js | 59 KB | 22 KB (38%) | ✓ | 3rd |
| https://ctlive.sky.it/livechat/SKY/lib/core/liveChatProtocol.js | 24 KB | 21 KB (88%) | ✗ | 3rd |
| https://www.sky.it/_next/static/chunks/2071.a895b1b88d250427.js | 2 KB | — | ✓ | 3rd |
Consider code splitting or tree shaking to reduce unused code.
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.
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.
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.
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.
This bundle has high unused code — code-split or tree-shake to ship only what executes.
Source: web.dev / Lighthouse coverage
FPage Weight InventoryAction182 resources · 2.8 MB · 449 KB savings availableFIX
~448.7 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 182 resources | 2.8 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
BImage Optimization18 images, 0 KB saveableREVIEW
Set explicit width and height to prevent CLS.
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
CJS Execution CostAction1792ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://cerebro-platform.sky.it/static/content/sp/js/common.js?async&seed=AAALNbedAQAA5bC2LTkP75sTg1ADGv6F_7irX-HpCaaN-E_h7qUmS7juXFt4&IshafTpPXs--z=q | 562ms | 527ms | 6ms | 3rd |
| https://www.sky.it/_next/static/chunks/framework-35048067b0fccd1f.js | 422ms | 223ms | 4ms | 3rd |
| Unattributable | 161ms | 4ms | 0ms | 3rd |
| https://www.sky.it/ | 149ms | 14ms | 1ms | 3rd |
| https://cmp.sky.it/Notice.8f529.js | 104ms | 72ms | 10ms | 3rd |
| https://assets.adobedtm.com/27331c16692c/d6621d9f42c4/launch-19ddb1c8c4b6.min.js | 103ms | 76ms | 13ms | 3rd |
| https://www.sky.it/_next/static/chunks/281c3f4d-41ed0b65a9fdac4d.js | 99ms | 23ms | 1ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-RWMN51KW03 | 87ms | 75ms | 12ms | 3rd |
| https://www.sky.it/_next/static/chunks/pages/index-65f273f2d870ca8e.js | 54ms | 52ms | 0ms | 3rd |
| https://www.sky.it/_next/static/chunks/pages/_app-71ef376c6516b45f.js | 52ms | 39ms | 12ms | 3rd |
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
A+Text CompressionAll text resources are compressedPASS
A+Font Loading16 fonts (563 KB)PASS
Web fonts
16
563 KB total
Render-blocking
0
of 16
Dominant font-display
swap
Most common across fonts
Font loading timeline
- Convert to woff2 for ~30% smaller file size
- Convert to woff2 for ~30% smaller file size
- Convert to woff2 for ~30% smaller file size
- Convert to woff2 for ~30% smaller file size
- Convert to woff2 for ~30% smaller file size
- Convert to woff2 for ~30% smaller file size
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 ~66 KB and ~132 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
Network Waterfall182 requests over 4040msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
cerebro-platform.sky.it cerebro-platform.sky.it | Other | 562ms | 160 KB | — | €9/mo | Costly |
www.sky.it www.sky.it | Other | 422ms | 59 KB | 38% | €7/mo | Costly |
Unattributable Unattributable | Other | 161ms | 0 KB | — | €3/mo | Optional |
www.sky.it www.sky.it | Other | 149ms | 72 KB | — | €2/mo | Optional |
cmp.sky.it cmp.sky.it | Other | 104ms | 91 KB | 67% | €2/mo | Optional |
assets.adobedtm.com assets.adobedtm.com | Other | 103ms | 74 KB | — | €2/mo | Optional |
www.sky.it www.sky.it | Other | 99ms | 20 KB | — | €2/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 87ms | 176 KB | 37% | €1/mo | Optional |
www.sky.it www.sky.it | Other | 54ms | 1 KB | — | €1/mo | Optional |
www.sky.it www.sky.it | Other | 52ms | 175 KB | 62% | €1/mo | Optional |
These scripts may cost more than they're worth
- cerebro-platform.sky.it adds 562ms and costs ~€9/month
- www.sky.it adds 422ms and costs ~€7/month
100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
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
cerebro-platform.sky.it takes 562ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
www.sky.it takes 422ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
67% of cmp.sky.it's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
62% of www.sky.it's code is unused. The script may be loading features you don't use.
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev