Performance
· 17 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.
3.33 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
22.00 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
1.44 s
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.
8.79 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.
29.73 s
Page Load Progression
FPage Weight BudgetAction6.1 MB transferred, 98 requestsFIX
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
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
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
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
FJS Execution CostAction11193ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://cdn.jsdelivr.net/npm/swiper@11/swiper-bundle.min.js | 3599ms | 1651ms | 61ms | 3rd |
| https://www.vatican.va/etc/clientlibs/granite/jquery.min.e0cc37eb1ac1cf9f859edde97cb8dc9f.js | 2539ms | 1724ms | 25ms | 3rd |
| https://www.vatican.va/content/vatican/en.html | 1618ms | 617ms | 6ms | 3rd |
| Unattributable | 1141ms | 115ms | 0ms | 3rd |
| https://www.vatican.va/etc/designs/vatican/library/clientlibs/themes/homepage_popes/js/webfont.js | 598ms | 46ms | 3ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-CGNTFB4GZQ&cx=c>m=4e64h1 | 592ms | 376ms | 116ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-P8S9M8D | 357ms | 271ms | 83ms | 3rd |
| https://vatican.va/etc/designs/vatican/library/clientlibs.min.a048ef155d62651cae0435360a52b70c.js | 227ms | 111ms | 76ms | 1st |
| https://www.vatican.va/etc/designs/vatican/library/clientlibs.min.a048ef155d62651cae0435360a52b70c.js | 203ms | 110ms | 74ms | 3rd |
| https://www.vatican.va/etc/designs/vaticanevents/library/clientlibs.min.462e7d1f2f7e05231a7d7f9f8f68e6aa.js | 126ms | 53ms | 50ms | 3rd |
Showing top 10 of 13 scripts
FJS BundlesAction32 scripts, 515 KB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.vatican.va/etc/designs/vaticanevents/library/clientlibs.min.462e7d1f2f7e05231a7d7f9f8f68e6aa.js | 106 KB | 91 KB (86%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-P8S9M8D | 0 KB | 63 KB (54%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-P8S9M8D | 118 KB | 63 KB (54%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-CGNTFB4GZQ&cx=c>m=4e64h1 | 0 KB | 63 KB (42%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-CGNTFB4GZQ&cx=c>m=4e64h1 | 152 KB | 63 KB (42%) | ✓ | 3rd |
| https://www.vatican.va/etc/designs/generics2/library/clientlibs.min.3c4d948cc1ae00387817c605328e2b0b.js | 0 KB | 35 KB (87%) | ✓ | 3rd |
| https://www.vatican.va/etc/designs/generics2/library/clientlibs.min.3c4d948cc1ae00387817c605328e2b0b.js | 40 KB | 35 KB (87%) | ✓ | 3rd |
| https://cdn.jsdelivr.net/npm/swiper@11/swiper-bundle.min.js | 43 KB | 26 KB (61%) | ✓ | 3rd |
| https://www.vatican.va/etc/designs/vatican/library/clientlibs.min.a048ef155d62651cae0435360a52b70c.js | 135 KB | 26 KB (20%) | ✓ | 3rd |
| https://www.vatican.va/etc/designs/vatican/library/clientlibs.min.a048ef155d62651cae0435360a52b70c.js | 0 KB | 26 KB (20%) | ✓ | 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 InventoryAction98 resources · 6.1 MB · 515 KB savings availableFIX
~515.0 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 98 resources | 6.1 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction13 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
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 (1279 KB)PASS
Web fonts
12
1279 KB total
Render-blocking
0
of 12
Dominant font-display
swap
Most common across fonts
Font loading timeline
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
- Convert to woff2 for ~30% smaller file size
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
- Convert to woff2 for ~30% smaller file size
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
- Convert to woff2 for ~30% smaller file size
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
- Convert to woff2 for ~30% smaller file size
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
- 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
- Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
- 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 ~844 KB and ~1688 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
A+Render-Blocking ResourcesNo render-blocking resources detectedPASS
A+Third-Party ResourcesNo third-party resources detectedPASS
Network Waterfall98 requests over 8894msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
jsDelivr cdn.jsdelivr.net | CDN | 3599ms | 43 KB | 61% | $48/mo | Costly |
www.vatican.va www.vatican.va | Other | 2539ms | 0 KB | — | $34/mo | Costly |
www.vatican.va www.vatican.va | Other | 1618ms | 19 KB | — | $21/mo | Costly |
Unattributable Unattributable | Other | 1141ms | 0 KB | — | $15/mo | Costly |
www.vatican.va www.vatican.va | Other | 598ms | 7 KB | — | $8/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 592ms | 0 KB | 42% | $8/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 357ms | 0 KB | 54% | $5/mo | Costly |
www.vatican.va www.vatican.va | Other | 203ms | 0 KB | 20% | $3/mo | Costly |
www.vatican.va www.vatican.va | Other | 126ms | 106 KB | 86% | $2/mo | Optional |
www.vatican.va www.vatican.va | Other | 71ms | 39 KB | 66% | $1/mo | Optional |
www.vatican.va www.vatican.va | Other | 69ms | 0 KB | 87% | $1/mo | Optional |
These scripts may cost more than they're worth
- jsDelivr adds 3599ms and costs ~$48/month
- www.vatican.va adds 2539ms and costs ~$34/month
- www.vatican.va adds 1618ms and costs ~$21/month
- Unattributable adds 1141ms and costs ~$15/month
- www.vatican.va adds 598ms and costs ~$8/month
- Google Tag Manager adds 592ms and costs ~$8/month
- Google Tag Manager adds 357ms and costs ~$5/month
- www.vatican.va adds 203ms and costs ~$3/month
97% 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
jsDelivr takes 3599ms 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
61% of jsDelivr'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.vatican.va takes 2539ms 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.vatican.va takes 1618ms 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
Unattributable takes 1141ms 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.vatican.va takes 598ms 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
Google Tag Manager takes 592ms 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
Google Tag Manager takes 357ms 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
54% of Google Tag Manager'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.vatican.va takes 203ms 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
86% of www.vatican.va'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
66% of www.vatican.va'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
87% of www.vatican.va'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