Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.
No Cache-Control header
Adding a Cache-Control header can significantly improve repeat-visit performance.
C
Image Optimization
Action
21 images, 0 KB saveable
REVIEW
21 images, 0 KB saveable
Warning::
!
https://www.rtl.de/img/30661309/1775037731/c16_9/4... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.rtl.de/img/30270045/1769075940/c16_9/4... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.rtl.de/img/30369169/1771261774/c16_9/4... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.rtl.de/img/30412947/1772201956/o is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
21images530 KB
0oversized-0 KB
7legacy format
4missing dimensionsCLS risk
Set explicit width and height to prevent CLS.
Why this matters
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.
Why this matters
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.
Why this matters
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.
Why this matters
Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.
Source: web.dev / Core Web Vitals
C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW
Green Hosting
No green hosting detected
A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
✓
All text resources are compressed
All text resources are properly compressed.
A+
Font Loading
2 fonts (58 KB)
PASS
2 fonts (58 KB)
Info::
i
2 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
2
58 KB total
Render-blocking
0
of 2
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
a839df46a297a209-s.p.woff2woff2swap
Size29 KB
Load time76 ms
Start765 ms
RiskFOUT — text flashes from fallback to web font
e96cda5e69a70db3-s.p.woff2woff2swap
Size28 KB
Load time77 ms
Start766 ms
RiskFOUT — text flashes from fallback to web font
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 Caching
All resources properly cached
PASS
All resources properly cached
Info::
✓
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
✓
No render-blocking resources detected
A+
Resource Hints
15 hints, 0 missing preconnects
PASS
15 hints, 0 missing preconnects
Info::
✓
Page uses 15 resource hint(s)
Current Resource Hints
preconnect—
preload
+5
15
dns-prefetch—
prefetch—
15 resource hints configured
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
✓
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
Network Waterfall
64 requests over 4117ms
INFO
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100%of JavaScript execution is third-party
First-party Third-party5303ms · 1755KB · €58/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
www.rtl.de
www.rtl.de
Other
1823ms
905 KB
—
€20/mo
Costly
cdn.rtl.de
cdn.rtl.de
Other
756ms
47 KB
48%
€8/mo
Costly
Unattributable
Unattributable
Other
607ms
0 KB
—
€7/mo
Costly
sourcepoint.rtl.de
sourcepoint.rtl.de
Other
355ms
91 KB
68%
€4/mo
Costly
cdn.rtl.de
cdn.rtl.de
Other
335ms
59 KB
37%
€4/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
305ms
145 KB
42%
€3/mo
Costly
www.rtl.de
www.rtl.de
Other
297ms
79 KB
70%
€3/mo
Costly
www.rtl.de
www.rtl.de
Other
233ms
130 KB
61%
€3/mo
Costly
njrkf6rvmq.kameleoon.eu
njrkf6rvmq.kameleoon.eu
Other
208ms
43 KB
—
€2/mo
Costly
www.rtl.de
www.rtl.de
Other
162ms
159 KB
54%
€2/mo
Optional
sourcepoint.rtl.de
sourcepoint.rtl.de
Other
146ms
40 KB
—
€2/mo
Optional
cdn-gl.nmrodam.com
cdn-gl.nmrodam.com
Other
75ms
56 KB
42%
€1/mo
Optional
www.rtl.de
Other
Costly
Execution1823ms
Transfer905 KB
Monthly Cost€20/mo
cdn.rtl.de
Other
Costly
Execution756ms
Transfer47 KB
Unused48%
Monthly Cost€8/mo
Unattributable
Other
Costly
Execution607ms
Transfer0 KB
Monthly Cost€7/mo
sourcepoint.rtl.de
Other
Costly
Execution355ms
Transfer91 KB
Unused68%
Monthly Cost€4/mo
cdn.rtl.de
Other
Costly
Execution335ms
Transfer59 KB
Unused37%
Monthly Cost€4/mo
Google Tag Manager
Tag Manager
Costly
Execution305ms
Transfer145 KB
Unused42%
Monthly Cost€3/mo
www.rtl.de
Other
Costly
Execution297ms
Transfer79 KB
Unused70%
Monthly Cost€3/mo
www.rtl.de
Other
Costly
Execution233ms
Transfer130 KB
Unused61%
Monthly Cost€3/mo
njrkf6rvmq.kameleoon.eu
Other
Costly
Execution208ms
Transfer43 KB
Monthly Cost€2/mo
www.rtl.de
Other
Optional
Execution162ms
Transfer159 KB
Unused54%
Monthly Cost€2/mo
sourcepoint.rtl.de
Other
Optional
Execution146ms
Transfer40 KB
Monthly Cost€2/mo
cdn-gl.nmrodam.com
Other
Optional
Execution75ms
Transfer56 KB
Unused42%
Monthly Cost€1/mo
These scripts may cost more than they're worth
www.rtl.de adds 1823ms and costs ~€20/month
cdn.rtl.de adds 756ms and costs ~€8/month
Unattributable adds 607ms and costs ~€7/month
sourcepoint.rtl.de adds 355ms and costs ~€4/month
cdn.rtl.de adds 335ms and costs ~€4/month
Google Tag Manager adds 305ms and costs ~€3/month
www.rtl.de adds 297ms and costs ~€3/month
www.rtl.de adds 233ms and costs ~€3/month
njrkf6rvmq.kameleoon.eu adds 208ms and costs ~€2/month
100% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.
Why this matters
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.rtl.de takes 1823ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
cdn.rtl.de takes 756ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Unattributable takes 607ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
sourcepoint.rtl.de takes 355ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
68% of sourcepoint.rtl.de's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
cdn.rtl.de takes 335ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
Google Tag Manager takes 305ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
www.rtl.de takes 297ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
70% of www.rtl.de's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
www.rtl.de takes 233ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
61% of www.rtl.de's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.
Source: web.dev
njrkf6rvmq.kameleoon.eu takes 208ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.
Why this matters
This script has high main-thread execution time — optimize hot paths or defer.
Source: web.dev
54% of www.rtl.de's code is unused. The script may be loading features you don't use.
Why this matters
Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.