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.
918 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.41 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
20 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.002
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
1.19 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.
1.65 s
Page Load Progression
DThird-Party ImpactAction100% third-party, 0 ms blockingFIX
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
BPage Weight Budget1.3 MB transferred, 104 requestsREVIEW
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
BImage Optimization16 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.
Performance issues directly impact user engagement and conversion rates.
CJS Execution CostAction1604ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.welt.de/ | 877ms | 34ms | 6ms | 3rd |
| https://www.welt.de/assets/bff-section/scripts/section.module.BkCq1DgY.js | 253ms | 125ms | 0ms | 3rd |
| https://rosetta.prod.ps.welt.de/ps-rosetta.js | 182ms | 177ms | 1ms | 3rd |
| Unattributable | 170ms | 21ms | 0ms | 3rd |
| https://ast.welt.de/welt/prod/utag.js | 61ms | 55ms | 5ms | 3rd |
| https://www.asadcdn.com/adlib/pages/welt.js?1 | 60ms | 51ms | 2ms | 3rd |
BJS Bundles59 scripts, 101 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.welt.de/assets/bff-section/scripts/section.module.BkCq1DgY.js | 115 KB | 50 KB (44%) | ✓ | 3rd |
| https://jnt.welt.de/get/live/web/_/6pzfc2.js | 36 KB | 29 KB (82%) | ✓ | 3rd |
| https://ast.welt.de/welt/prod/utag.js | 60 KB | 22 KB (37%) | ✓ | 3rd |
| https://consent.up.welt.de/unified/wrapperMessagingWithoutDetection.js | 42 KB | — | ✓ | 3rd |
| https://www.asadcdn.com/adlib/pages/welt.js?1 | 29 KB | — | ✓ | 3rd |
| https://rosetta.prod.ps.welt.de/ps-rosetta.js | 16 KB | — | ✓ | 3rd |
| https://www.asadcdn.com/pec/currency.js | 2 KB | — | ✓ | 3rd |
| https://www.asadcdn.com/adlib/libmodules/desktop/addCSS.52213e56.js | 0 KB | — | ✓ | 3rd |
| https://www.asadcdn.com/adlib/libmodules/desktop/calcY.7baffa20.js | 0 KB | — | ✓ | 3rd |
| https://www.asadcdn.com/adlib/libmodules/desktop/enrichPTV.a18a82bb.js | 1 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
CPage Weight InventoryAction104 resources · 1.3 MB · 101 KB savings availableREVIEW
~101.4 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 104 resources | 1.3 MiB | ||||||
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 Loading4 fonts (92 KB)PASS
Web fonts
4
92 KB total
Render-blocking
0
of 4
Dominant font-display
swap
Most common across fonts
Font loading timeline
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 CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
Network Waterfall104 requests over 2833msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.welt.de www.welt.de | Other | 877ms | 169 KB | — | €4/mo | Costly |
www.welt.de www.welt.de | Other | 253ms | 115 KB | 44% | €1/mo | Costly |
rosetta.prod.ps.welt.de rosetta.prod.ps.welt.de | Other | 182ms | 16 KB | — | €1/mo | Optional |
Unattributable Unattributable | Other | 170ms | 0 KB | — | €1/mo | Optional |
ast.welt.de ast.welt.de | Other | 61ms | 60 KB | 37% | €0/mo | Optional |
www.asadcdn.com www.asadcdn.com | Other | 60ms | 29 KB | — | €0/mo | Optional |
These scripts may cost more than they're worth
- www.welt.de adds 877ms and costs ~€4/month
- www.welt.de adds 253ms and costs ~€1/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
www.welt.de takes 877ms 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.welt.de takes 253ms 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