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
31 images, 0 KB saveable
REVIEW
31 images, 0 KB saveable
Warning::
!
https://wwwimage-tve.cbsstatic.com/thumbnails/phot... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://wwwimage-tve.cbsstatic.com/thumbnails/phot... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://wwwimage-tve.cbsstatic.com/thumbnails/phot... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://wwwimage-tve.cbsstatic.com/thumbnails/phot... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://wwwimage-tve.cbsstatic.com/thumbnails/phot... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://wwwimage-tve.cbsstatic.com/thumbnails/phot... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://wwwimage-tve.cbsstatic.com/thumbnails/phot... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://wwwimage-tve.cbsstatic.com/thumbnails/phot... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://wwwimage-tve.cbsstatic.com/thumbnails/phot... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://wwwimage-tve.cbsstatic.com/thumbnails/phot... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://wwwimage-tve.cbsstatic.com/thumbnails/phot... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://wwwimage-tve.cbsstatic.com/thumbnails/phot... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://wwwimage-tve.cbsstatic.com/thumbnails/phot... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://wwwimage-tve.cbsstatic.com/thumbnails/phot... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
31images729 KB
0oversized-0 KB
23legacy format
14missing 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
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
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
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
4 fonts (154 KB)
PASS
4 fonts (154 KB)
Info::
i
4 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
4
154 KB total
Render-blocking
0
of 4
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
woff2;base64,d09GMgABAA...woff2swap
Size40 KB
Load time74 ms
Start222 ms
RiskFOUT — text flashes from fallback to web font
woff2;base64,d09GMgABAA...woff2swap
Size40 KB
Load time78 ms
Start223 ms
RiskFOUT — text flashes from fallback to web font
woff2;base64,d09GMgABAA...woff2swap
Size40 KB
Load time86 ms
Start224 ms
RiskFOUT — text flashes from fallback to web font
KFO7CnqEu92Fr1ME7kSn66a...woff2swap
Size34 KB
Load time23 ms
Start1.4 s
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
4 hints, 0 missing preconnects
PASS
4 hints, 0 missing preconnects
Info::
✓
Page uses 4 resource hint(s)
Current Resource Hints
preconnect—
preload—
dns-prefetch—
prefetch
4
4 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
100 requests over 1988ms
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-party7442ms · 1156KB · €81/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
www.cbs.com
www.cbs.com
Other
1772ms
41 KB
—
€19/mo
Costly
www.gstatic.com
www.gstatic.com
Other
1119ms
0 KB
49%
€12/mo
Costly
Unattributable
Unattributable
Other
1116ms
0 KB
—
€12/mo
Costly
www.cbs.com
www.cbs.com
Other
831ms
160 KB
52%
€9/mo
Costly
cdn.ketchjs.com
cdn.ketchjs.com
Other
803ms
257 KB
58%
€9/mo
Costly
tags.tiqcdn.com
tags.tiqcdn.com
Other
374ms
190 KB
60%
€4/mo
Costly
www.cbs.com
www.cbs.com
Other
333ms
146 KB
65%
€4/mo
Costly
Facebook Pixel
connect.facebook.net
Advertising
240ms
97 KB
45%
€3/mo
Costly
tags.tiqcdn.com
tags.tiqcdn.com
Other
236ms
3 KB
—
€3/mo
Costly
www.cbs.com
www.cbs.com
Other
226ms
209 KB
82%
€2/mo
Costly
cdn.privacy.paramount.com
cdn.privacy.paramount.com
Other
214ms
9 KB
—
€2/mo
Costly
Facebook Pixel
connect.facebook.net
Advertising
179ms
44 KB
47%
€2/mo
Optional
www.cbs.com
Other
Costly
Execution1772ms
Transfer41 KB
Monthly Cost€19/mo
www.gstatic.com
Other
Costly
Execution1119ms
Transfer0 KB
Unused49%
Monthly Cost€12/mo
Unattributable
Other
Costly
Execution1116ms
Transfer0 KB
Monthly Cost€12/mo
www.cbs.com
Other
Costly
Execution831ms
Transfer160 KB
Unused52%
Monthly Cost€9/mo
cdn.ketchjs.com
Other
Costly
Execution803ms
Transfer257 KB
Unused58%
Monthly Cost€9/mo
tags.tiqcdn.com
Other
Costly
Execution374ms
Transfer190 KB
Unused60%
Monthly Cost€4/mo
www.cbs.com
Other
Costly
Execution333ms
Transfer146 KB
Unused65%
Monthly Cost€4/mo
Facebook Pixel
Advertising
Costly
Execution240ms
Transfer97 KB
Unused45%
Monthly Cost€3/mo
tags.tiqcdn.com
Other
Costly
Execution236ms
Transfer3 KB
Monthly Cost€3/mo
www.cbs.com
Other
Costly
Execution226ms
Transfer209 KB
Unused82%
Monthly Cost€2/mo
cdn.privacy.paramount.com
Other
Costly
Execution214ms
Transfer9 KB
Monthly Cost€2/mo
Facebook Pixel
Advertising
Optional
Execution179ms
Transfer44 KB
Unused47%
Monthly Cost€2/mo
These scripts may cost more than they're worth
www.cbs.com adds 1772ms and costs ~€19/month
www.gstatic.com adds 1119ms and costs ~€12/month
Unattributable adds 1116ms and costs ~€12/month
www.cbs.com adds 831ms and costs ~€9/month
cdn.ketchjs.com adds 803ms and costs ~€9/month
tags.tiqcdn.com adds 374ms and costs ~€4/month
www.cbs.com adds 333ms and costs ~€4/month
Facebook Pixel adds 240ms and costs ~€3/month
tags.tiqcdn.com adds 236ms and costs ~€3/month
www.cbs.com adds 226ms and costs ~€2/month
cdn.privacy.paramount.com adds 214ms 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.cbs.com takes 1772ms 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.gstatic.com takes 1119ms 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 1116ms 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.cbs.com takes 831ms 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
52% of www.cbs.com'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.ketchjs.com takes 803ms 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
58% of cdn.ketchjs.com'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
tags.tiqcdn.com takes 374ms 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
60% of tags.tiqcdn.com'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.cbs.com takes 333ms 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
65% of www.cbs.com'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
Facebook Pixel takes 240ms 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
tags.tiqcdn.com takes 236ms 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.cbs.com takes 226ms 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
82% of www.cbs.com'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.privacy.paramount.com takes 214ms 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.