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.
783 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
886 ms
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
0 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.
2.40 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.
889 ms
Page Load Progression
731 ms 1.5 s 2.2 s 2.9 s
3.7 s
4.4 s
5.1 s
5.8 sDThird-Party ImpactAction100% third-party, 0 ms blockingFIX
DPage Weight InventoryAction32 resources · 1.5 MB · 87 KB savings availableFIX
~86.8 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 32 resources | 1.5 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
BPage Weight Budget1.5 MB transferred, 32 requestsREVIEW
CImage OptimizationAction10 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
CJS Execution CostAction1591ms total JS executionREVIEW
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.fes.de/_assets/39d34273ab30c098def3e42400bf98d1/dist/lottie-player.js?1775824734 | 1393ms | 1296ms | 9ms | 3rd |
| Unattributable | 106ms | 10ms | 0ms | 3rd |
| https://www.fes.de/ | 92ms | 2ms | 0ms | 3rd |
CJS BundlesAction7 scripts, 87 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.fes.de/_assets/39d34273ab30c098def3e42400bf98d1/dist/lottie-player.js?1775824734 | 52 KB | 48 KB (94%) | ✓ | 3rd |
| https://www.fes.de/_assets/vite/desktop-navigation.js | 48 KB | 39 KB (81%) | ✗ | 3rd |
| https://www.fes.de/_assets/9cec337f7d9b8a112ff7bc4a21068e10/Libs/eye-able-tool.js?1775824733 | 5 KB | — | ✓ | 3rd |
| https://www.fes.de/typo3temp/assets/js/7378d5dc5468da27b323e43dae530540.js?1763973398 | 2 KB | — | ✓ | 3rd |
| https://www.fes.de/_assets/vite/fes-theme.js | 24 KB | — | ✗ | 3rd |
| https://www.fes.de/_assets/e8c90b9983c1cf95dcc0174e76f0c198/JavaScript/cookie_consent.js?1771504436 | 4 KB | — | ✓ | 3rd |
| https://www.fes.de/_assets/vite/_commonjsHelpers.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
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 Loading3 fonts (91 KB)PASS
Web fonts
3
91 KB total
Render-blocking
0
of 3
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 Waterfall32 requests over 3517msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.fes.de www.fes.de | Other | 1393ms | 52 KB | 94% | €15/mo | Costly |
Unattributable Unattributable | Other | 106ms | 0 KB | — | €1/mo | Optional |
www.fes.de www.fes.de | Other | 92ms | 37 KB | — | €1/mo | Optional |
These scripts may cost more than they're worth
- www.fes.de adds 1393ms and costs ~€15/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.fes.de takes 1393ms 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
94% of www.fes.de'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