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.
1.09 s
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
2.21 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
559 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.085
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
2.19 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.
2.82 s
Page Load Progression
430 ms
859 ms
1.3 s
1.7 s
2.1 s 2.6 s
3.0 s
3.4 sFPage Weight BudgetAction8.6 MB transferred, 299 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
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
DJS Execution CostAction3223ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://www.zdf.de/ | 1142ms | 53ms | 119ms | 3rd |
| https://www.zdf.de/_next/static/chunks/0_2coxc~qrg~_.js | 1130ms | 966ms | 6ms | 3rd |
| https://www.zdf.de/_next/static/chunks/131j6musa7dd5.js | 518ms | 196ms | 6ms | 3rd |
| Unattributable | 382ms | 8ms | 0ms | 3rd |
| https://www.zdf.de/_next/static/chunks/0edj_du0i_55v.js | 51ms | 11ms | 1ms | 3rd |
DPage Weight InventoryAction299 resources · 8.6 MB · 235 KB savings availableFIX
~235.3 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 299 resources | 8.6 MiB | ||||||
FHTTP CachingActionNo cache headersFIX
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
BImage Optimization152 images, 0 KB saveableREVIEW
CJS BundlesAction46 scripts, 235 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://www.zdf.de/_next/static/chunks/0q9m_l9nd-wja.js | 106 KB | 92 KB (87%) | ✓ | 3rd |
| https://www.zdf.de/_next/static/chunks/131j6musa7dd5.js | 67 KB | 40 KB (61%) | ✓ | 3rd |
| https://www.zdf.de/_next/static/chunks/0zf3l5jxz4xfr.js | 65 KB | 33 KB (51%) | ✓ | 3rd |
| https://www.zdf.de/_next/static/chunks/0azjtpyz1uhki.js | 49 KB | 24 KB (50%) | ✓ | 3rd |
| https://www.zdf.de/_next/static/chunks/0_2coxc~qrg~_.js | 72 KB | 24 KB (34%) | ✓ | 3rd |
| https://www.zdf.de/_next/static/chunks/0nllr2zvvosbo.js | 40 KB | 21 KB (54%) | ✓ | 3rd |
| https://www.zdf.de/_next/static/chunks/06gz7xdkdnn96.js | 11 KB | — | ✓ | 3rd |
| https://www.zdf.de/_next/static/chunks/0-qm0opuay_wj.js | 20 KB | — | ✓ | 3rd |
| https://www.zdf.de/_next/static/chunks/00azre-83z217.js | 33 KB | — | ✓ | 3rd |
| https://www.zdf.de/_next/static/chunks/turbopack-0aj.nhhe.7oy3.js | 5 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
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 Loading13 fonts (345 KB)PASS
Web fonts
13
345 KB total
Render-blocking
0
of 13
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 Waterfall299 requests over 3415msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
www.zdf.de www.zdf.de | Other | 1142ms | 428 KB | — | €5/mo | Costly |
www.zdf.de www.zdf.de | Other | 1130ms | 72 KB | 34% | €5/mo | Costly |
www.zdf.de www.zdf.de | Other | 518ms | 67 KB | 61% | €2/mo | Costly |
Unattributable Unattributable | Other | 382ms | 0 KB | — | €2/mo | Costly |
www.zdf.de www.zdf.de | Other | 51ms | 14 KB | — | €0/mo | Optional |
These scripts may cost more than they're worth
- www.zdf.de adds 1142ms and costs ~€5/month
- www.zdf.de adds 1130ms and costs ~€5/month
- www.zdf.de adds 518ms and costs ~€2/month
- Unattributable adds 382ms and costs ~€2/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.zdf.de takes 1142ms 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.zdf.de takes 1130ms 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.zdf.de takes 518ms 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 www.zdf.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
Unattributable takes 382ms 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