Performance
· 22 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.
2.10 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
4.23 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
849 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.003
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
4.93 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.
6.02 s
Page Load Progression
FPage Weight BudgetAction4.1 MB transferred, 236 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
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.
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
Remove unused CSS rules with tools like PurgeCSS to reduce stylesheet size.
CSS bundle is large — purge unused styles (PurgeCSS, Tailwind JIT) to reduce CSS payload.
Source: web.dev
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 Execution CostAction5757ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.enel.it/etc.clientlibs/enel-comm-common/clientlibs/clientlib-chat.min.js | 1089ms | 1063ms | 5ms | 3rd |
| Unattributable | 725ms | 49ms | 0ms | 1st |
| https://www.gstatic.com/recaptcha/releases/rL1ELiQAg1kPezz6_H9hTZ_i/recaptcha__en.js | 709ms | 506ms | 78ms | 3rd |
| https://www.enel.it/etc.clientlibs/clientlibs/granite/jquery/granite/csrf.min.js | 621ms | 583ms | 1ms | 3rd |
| https://www.enel.it/it-it | 568ms | 17ms | 0ms | 3rd |
| https://www.enel.it/trous-Quings-Reuolted-Hence-is-the-earth-herefor | 529ms | 492ms | 18ms | 3rd |
| https://www.enel.it/ruxitagentjs_ICA27NVfghjoqrux_10263230921131557.js | 486ms | 369ms | 18ms | 3rd |
| https://www.enel.it/etc.clientlibs/enel-ita/clientlibs/clientlib-dependencies.min.js | 252ms | 244ms | 5ms | 3rd |
| https://www.enel.it/etc.clientlibs/enel-common-lib/clientlibs/clientlib-dynamic-modules/resources/7059.js | 227ms | 52ms | 4ms | 3rd |
| https://www.enel.it/lepis/ | 196ms | 178ms | 17ms | 3rd |
Showing top 10 of 14 scripts
FJS BundlesAction90 scripts, 987 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.gstatic.com/recaptcha/releases/rL1ELiQAg1kPezz6_H9hTZ_i/recaptcha__en.js | 0 KB | 186 KB (50%) | ✓ | 3rd |
| https://www.gstatic.com/recaptcha/releases/rL1ELiQAg1kPezz6_H9hTZ_i/recaptcha__en.js | 375 KB | 186 KB (50%) | ✓ | 3rd |
| https://www.gstatic.com/recaptcha/releases/rL1ELiQAg1kPezz6_H9hTZ_i/recaptcha__en.js | 374 KB | 186 KB (50%) | ✓ | 3rd |
| https://www.enel.it/luffy/ | 152 KB | 73 KB (48%) | ✓ | 3rd |
| https://www.enel.it/mjojo/ | 145 KB | 73 KB (50%) | ✓ | 3rd |
| https://www.enel.it/lepis/ | 158 KB | 70 KB (44%) | ✓ | 3rd |
| https://www.enel.it/etc.clientlibs/enel-common-lib/clientlibs/clientlib-dependencies.min.js | 45 KB | 34 KB (76%) | ✓ | 3rd |
| https://www.enel.it/ruxitagentjs_ICA27NVfghjoqrux_10263230921131557.js | 97 KB | 33 KB (34%) | ✓ | 3rd |
| https://www.enel.it/etc.clientlibs/enel-common-lib/clientlibs/clientlib-site.min.js | 43 KB | 28 KB (67%) | ✓ | 3rd |
| https://assets.adobedtm.com/eeb01e5b93f1/d7043a597bc5/launch-af39fde06596.min.js | 97 KB | 28 KB (29%) | ✓ | 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 InventoryAction236 resources · 4.1 MB · 987 KB savings availableFIX
~986.7 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 236 resources | 4.1 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction79 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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
BHTTP/3 (QUIC)HTTP/3 not advertisedREVIEW
CCompression AlgorithmActionMain response served uncompressedREVIEW
BMain HTML Cache-ControlNo Cache-Control header on main HTML responseREVIEW
BServer-Timing ObservabilityNo Server-Timing header foundREVIEW
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 Loading12 fonts (417 KB)PASS
Web fonts
12
417 KB total
Render-blocking
0
of 12
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
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 ~36 KB and ~72 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
A+LCP Image PreloadLCP preload audit not availablePASS
A+Server Response Intelligence1 server-response signal(s) detectedPASS
Network Waterfall236 requests over 9446msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.enel.it www.enel.it | Other | 1089ms | 24 KB | 84% | €12/mo | Costly |
www.gstatic.com www.gstatic.com | Other | 709ms | 0 KB | 50% | €8/mo | Costly |
www.enel.it www.enel.it | Other | 621ms | 2 KB | — | €7/mo | Costly |
www.enel.it www.enel.it | Other | 568ms | 127 KB | — | €6/mo | Costly |
www.enel.it www.enel.it | Other | 529ms | 233 KB | — | €6/mo | Costly |
www.enel.it www.enel.it | Other | 486ms | 97 KB | 34% | €5/mo | Costly |
www.enel.it www.enel.it | Other | 252ms | 45 KB | 49% | €3/mo | Costly |
www.enel.it www.enel.it | Other | 227ms | 42 KB | 62% | €2/mo | Costly |
www.enel.it www.enel.it | Other | 196ms | 158 KB | 44% | €2/mo | Optional |
assets.adobedtm.com assets.adobedtm.com | Other | 118ms | 97 KB | 29% | €1/mo | Optional |
www.enel.it www.enel.it | Other | 99ms | 1 KB | — | €1/mo | Optional |
consent.trustarc.com consent.trustarc.com | Other | 84ms | 14 KB | — | €1/mo | Optional |
www.enel.it www.enel.it | Other | 55ms | 43 KB | 67% | €1/mo | Optional |
These scripts may cost more than they're worth
- www.enel.it adds 1089ms and costs ~€12/month
- www.gstatic.com adds 709ms and costs ~€8/month
- www.enel.it adds 621ms and costs ~€7/month
- www.enel.it adds 568ms and costs ~€6/month
- www.enel.it adds 529ms and costs ~€6/month
- www.enel.it adds 486ms and costs ~€5/month
- www.enel.it adds 252ms and costs ~€3/month
- www.enel.it adds 227ms and costs ~€2/month
87% 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
www.enel.it takes 1089ms 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
84% of www.enel.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
www.gstatic.com takes 709ms 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.enel.it takes 621ms 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.enel.it takes 568ms 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.enel.it takes 529ms 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.enel.it takes 486ms 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.enel.it takes 252ms 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.enel.it takes 227ms 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
62% of www.enel.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
67% of www.enel.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
Image Optimization200 images, 1119 KB total, 234 KB wastedINFO
Image Optimization Audit
Total Images
200
Total Size
1119 KB
Oversized
6
Wasted
234 KB