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.
2.73 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
2.73 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
997 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.099
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
4.16 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.
8.59 s
Page Load Progression
408 ms 817 ms
1.2 s
1.6 s 2.0 s 2.5 s 2.9 s
3.3 sFPage Weight BudgetAction5.0 MB transferred, 245 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
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 CostAction4372ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://cf.bstatic.com/psb/capla/static/js/client.1572d987.js | 1439ms | 1147ms | 65ms | 3rd |
| https://www.booking.com/?chal_t=1776359895891&force_referer= | 550ms | 49ms | 2ms | 3rd |
| Unattributable | 474ms | 106ms | 0ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-5Q664QZ | 311ms | 254ms | 24ms | 3rd |
| https://d8c14d4960ca.edge.sdk.awswaf.com/d8c14d4960ca/a18a4859af9c/challenge.js | 309ms | 246ms | 50ms | 3rd |
| https://cf.bstatic.com/psb/capla/static/js/782ad794.ea2f5e5f.chunk.js | 271ms | 233ms | 31ms | 3rd |
| https://www.booking.com/__challenge_h78IRKX3kpQxScCExxShBNwRUlb/d8c14d4960ca/a18a4859af9c/challenge.js | 258ms | 190ms | 46ms | 3rd |
| https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604140101/pubads_impl.js?cb=31097850 | 194ms | 165ms | 20ms | 3rd |
| https://cf.bstatic.com/psb/capla/static/js/remoteEntry.eeebe667.client.js | 125ms | 124ms | 1ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-A12345&cx=c>m=4e64f0&bs=ctrl | 107ms | 92ms | 13ms | 3rd |
Showing top 10 of 14 scripts
FJS BundlesAction91 scripts, 1.7 MB unusedFIX
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://d8c14d4960ca.edge.sdk.awswaf.com/d8c14d4960ca/a18a4859af9c/challenge.js | 489 KB | 284 KB (58%) | ✓ | 3rd |
| https://cf.bstatic.com/psb/capla/static/js/782ad794.ea2f5e5f.chunk.js | 224 KB | 215 KB (96%) | ✓ | 3rd |
| https://cf.bstatic.com/psb/capla/static/js/client.1572d987.js | 409 KB | 176 KB (43%) | ✓ | 3rd |
| https://cf.bstatic.com/psb/capla/static/js/c43f530f.2815a552.chunk.js | 224 KB | 143 KB (64%) | ✓ | 3rd |
| https://cf.bstatic.com/psb/capla/static/js/dc32f6b7.6d16fe38.chunk.js | 159 KB | 122 KB (77%) | ✓ | 3rd |
| https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604140101/pubads_impl.js?cb=31097850 | 188 KB | 107 KB (57%) | ✓ | 3rd |
| https://cf.bstatic.com/psb/capla/static/js/dceb1327.9d726c05.chunk.js | 122 KB | 78 KB (64%) | ✓ | 3rd |
| https://cdn.cookielaw.org/scripttemplates/202501.2.0/otBannerSdk.js | 114 KB | 74 KB (65%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/destination?id=DC-4228414&cx=c>m=4e64f0&bs=ctrl | 130 KB | 62 KB (48%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/destination?id=AW-988382855&cx=c>m=4e64f0&bs=ctrl | 146 KB | 61 KB (42%) | ✓ | 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 InventoryAction245 resources · 5.0 MB · 1.7 MB savings availableFIX
~1.7 MiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 245 resources | 5.0 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
CImage OptimizationAction36 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
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 LoadingNo web fonts (system fonts)PASS
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
Network Waterfall245 requests over 11111msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
cf.bstatic.com cf.bstatic.com | Other | 1439ms | 409 KB | 43% | €16/mo | Costly |
www.booking.com www.booking.com | Other | 550ms | 74 KB | — | €6/mo | Costly |
Unattributable Unattributable | Other | 474ms | 0 KB | — | €5/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 311ms | 181 KB | 27% | €3/mo | Costly |
d8c14d4960ca.edge.sdk.awswaf.com d8c14d4960ca.edge.sdk.awswaf.com | Other | 309ms | 489 KB | 58% | €3/mo | Costly |
cf.bstatic.com cf.bstatic.com | Other | 271ms | 224 KB | 96% | €3/mo | Costly |
www.booking.com www.booking.com | Other | 258ms | 506 KB | — | €3/mo | Costly |
securepubads.g.doubleclick.net securepubads.g.doubleclick.net | Other | 194ms | 188 KB | 57% | €2/mo | Optional |
cf.bstatic.com cf.bstatic.com | Other | 125ms | 7 KB | — | €1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 107ms | 137 KB | 43% | €1/mo | Optional |
cf.bstatic.com cf.bstatic.com | Other | 103ms | 1 KB | — | €1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 97ms | 146 KB | 42% | €1/mo | Optional |
cf.bstatic.com cf.bstatic.com | Other | 70ms | 3 KB | — | €1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 63ms | 130 KB | 48% | €1/mo | Optional |
These scripts may cost more than they're worth
- cf.bstatic.com adds 1439ms and costs ~€16/month
- www.booking.com adds 550ms and costs ~€6/month
- Unattributable adds 474ms and costs ~€5/month
- Google Tag Manager adds 311ms and costs ~€3/month
- d8c14d4960ca.edge.sdk.awswaf.com adds 309ms and costs ~€3/month
- cf.bstatic.com adds 271ms and costs ~€3/month
- www.booking.com adds 258ms and costs ~€3/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
cf.bstatic.com takes 1439ms 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.booking.com takes 550ms 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 474ms 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 311ms 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
d8c14d4960ca.edge.sdk.awswaf.com takes 309ms 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
58% of d8c14d4960ca.edge.sdk.awswaf.com'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
cf.bstatic.com takes 271ms 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
96% of cf.bstatic.com'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.booking.com takes 258ms 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
57% of securepubads.g.doubleclick.net'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