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.
982 ms
Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.
1.62 s
Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.
137 ms
Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.
0.647
Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.
3.04 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.
2.94 s
Page Load Progression
559 ms 1.1 s
1.7 s 2.2 s
2.8 s
3.4 s 3.9 s
4.5 sFPage Weight BudgetAction4.5 MB transferred, 126 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 CostAction2122ms total JS executionFIX
Main Thread Breakdown
| Script | Total | Scripting | Parse/Compile | Party |
|---|---|---|---|---|
| https://static.spektrum.de/js_css/assets/js/app.js | 612ms | 344ms | 17ms | 3rd |
| https://www.spektrum.de/ | 419ms | 18ms | 1ms | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-NV9D2M | 280ms | 222ms | 20ms | 3rd |
| Unattributable | 212ms | 4ms | 0ms | 3rd |
| https://cdn.cookielaw.org/scripttemplates/202604.1.0/otTCF.js | 167ms | 153ms | 2ms | 3rd |
| https://cdn.cookielaw.org/scripttemplates/202604.1.0/otBannerSdk.js | 166ms | 104ms | 16ms | 3rd |
| https://static.spektrum.de/js_css/iqd/cdn_spektrum_digt/live/iqadcontroller.js | 109ms | 69ms | 27ms | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-YXNVZ6NX0G&cx=c>m=4e64k1 | 105ms | 88ms | 16ms | 3rd |
| https://cdn.cookielaw.org/scripttemplates/otSDKStub.js?did=69405b66-21db-433c-a550-4b18074a0f51 | 50ms | 37ms | 1ms | 3rd |
DPage Weight InventoryAction126 resources · 4.5 MB · 295 KB savings availableFIX
~294.7 KiB of savings available
| # | Resource | Type | Size | Cache | Unused | 3rd party | Issues |
|---|---|---|---|---|---|---|---|
| — | — | ||||||
| 126 resources | 4.5 MiB | ||||||
CJS BundlesAction22 scripts, 295 KB unusedREVIEW
Downloaded but never executed on this page.
| Script | Size | Unused | Minified | Party |
|---|---|---|---|---|
| https://static.spektrum.de/js_css/assets/js/app.js | 140 KB | 94 KB (67%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtm.js?id=GTM-NV9D2M | 171 KB | 74 KB (44%) | ✓ | 3rd |
| https://www.googletagmanager.com/gtag/js?id=G-YXNVZ6NX0G&cx=c>m=4e64k1 | 172 KB | 65 KB (38%) | ✓ | 3rd |
| https://cdn.cookielaw.org/scripttemplates/202604.1.0/otBannerSdk.js | 131 KB | 62 KB (47%) | ✓ | 3rd |
| https://www.spektrum.de/js_css/ouibounce/ouibounce.min.js | 1 KB | — | ✓ | 3rd |
| https://assets.poool.fr/vendor-audit.min.js | 1 KB | — | ✓ | 3rd |
| https://static.spektrum.de/js_css/iqd/cdn_spektrum_digt/live/iqadcontroller.js | 69 KB | — | ✓ | 3rd |
| https://cdn.cookielaw.org/scripttemplates/202604.1.0/otTCF.js | 18 KB | — | ✓ | 3rd |
| https://assets.poool.fr/engage.min.js | 19 KB | — | ✓ | 3rd |
| https://assets.poool.fr/access.min.js | 31 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
CGreen HostingActionWhether the site is served from green-energy infrastructureREVIEW
Green Hosting
No green hosting detected
A+Text CompressionAll text resources are compressedPASS
AImage Optimization58 images, 0 KB saveablePASS
A+Font Loading15 fonts (497 KB)PASS
Web fonts
15
497 KB total
Render-blocking
0
of 15
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
- 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
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 ~136 KB and ~272 ms
A+Resource CachingAll resources properly cachedPASS
A+Critical Rendering PathNo render-blocking resourcesPASS
A+Resource HintsNo optimization neededPASS
AHTTP Cachingmax-age=86400 (1 day)PASS
max-age=86400
| Directive | Value | Meaning |
|---|---|---|
| max-age | 86400 | Cache for 1 day |
Network Waterfall126 requests over 4272msINFO
Third-Party Script CostPer-script blocking time, transfer cost, and cache headersINFO
| Script | Category | Execution | Transfer | Unused | Monthly Cost | Verdict |
|---|---|---|---|---|---|---|
static.spektrum.de static.spektrum.de | Other | 612ms | 140 KB | 67% | €7/mo | Costly |
www.spektrum.de www.spektrum.de | Other | 419ms | 33 KB | — | €5/mo | Costly |
Google Tag Manager www.googletagmanager.com | Tag Manager | 280ms | 171 KB | 44% | €3/mo | Costly |
Unattributable Unattributable | Other | 212ms | 0 KB | — | €2/mo | Costly |
OneTrust cdn.cookielaw.org | Consent | 167ms | 18 KB | — | €2/mo | Essential |
OneTrust cdn.cookielaw.org | Consent | 166ms | 131 KB | 47% | €2/mo | Essential |
static.spektrum.de static.spektrum.de | Other | 109ms | 69 KB | — | €1/mo | Optional |
Google Tag Manager www.googletagmanager.com | Tag Manager | 105ms | 172 KB | 38% | €1/mo | Optional |
OneTrust cdn.cookielaw.org | Consent | 50ms | 9 KB | — | €1/mo | Essential |
These scripts may cost more than they're worth
- static.spektrum.de adds 612ms and costs ~€7/month
- www.spektrum.de adds 419ms and costs ~€5/month
- Google Tag Manager adds 280ms and costs ~€3/month
- Unattributable adds 212ms 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
static.spektrum.de takes 612ms 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
67% of static.spektrum.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
www.spektrum.de takes 419ms 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 280ms 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 212ms 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