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
20 images, 0 KB saveable
REVIEW
20 images, 0 KB saveable
Warning::
!
https://www.opengroup.org/sites/default/files/the-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.opengroup.org/sites/default/files/blog... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.opengroup.org/sites/default/files/inli... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.opengroup.org/sites/default/files/inli... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.opengroup.org/sites/default/files/libr... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.opengroup.org/sites/default/files/inli... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.opengroup.org/sites/default/files/news... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.opengroup.org/sites/default/files/on-d... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
20images1.7 MB
0oversized-0 KB
17legacy format
8missing 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
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
1 fonts (38 KB)
PASS
1 fonts (38 KB)
Info::
i
1 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
1
38 KB total
Render-blocking
0
of 1
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
XRXV3I6Li01BKofINeaBTMn...woff2swap
Size38 KB
Load time42 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
No optimization needed
PASS
No optimization needed
Info::
✓
No resource hint issues
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
67 requests over 3489ms
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-party3806ms · 1908KB · $51/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
www.opengroup.org
www.opengroup.org
Other
1061ms
22 KB
—
$14/mo
Costly
Unattributable
Unattributable
Other
536ms
0 KB
—
$7/mo
Costly
www.opengroup.org
www.opengroup.org
Other
384ms
186 KB
67%
$5/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
293ms
158 KB
41%
$4/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
244ms
157 KB
43%
$3/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
233ms
156 KB
44%
$3/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
221ms
164 KB
41%
$3/mo
Costly
use.fontawesome.com
use.fontawesome.com
Other
181ms
611 KB
—
$2/mo
Optional
Google Tag Manager
www.googletagmanager.com
Tag Manager
179ms
146 KB
44%
$2/mo
Optional
Google Tag Manager
www.googletagmanager.com
Tag Manager
168ms
145 KB
44%
$2/mo
Optional
Google Tag Manager
www.googletagmanager.com
Tag Manager
147ms
125 KB
52%
$2/mo
Optional
www.statcounter.com
www.statcounter.com
Other
107ms
17 KB
—
$1/mo
Optional
Google Analytics
www.google-analytics.com
Analytics
52ms
21 KB
—
$1/mo
Optional
www.opengroup.org
Other
Costly
Execution1061ms
Transfer22 KB
Monthly Cost$14/mo
Unattributable
Other
Costly
Execution536ms
Transfer0 KB
Monthly Cost$7/mo
www.opengroup.org
Other
Costly
Execution384ms
Transfer186 KB
Unused67%
Monthly Cost$5/mo
Google Tag Manager
Tag Manager
Costly
Execution293ms
Transfer158 KB
Unused41%
Monthly Cost$4/mo
Google Tag Manager
Tag Manager
Costly
Execution244ms
Transfer157 KB
Unused43%
Monthly Cost$3/mo
Google Tag Manager
Tag Manager
Costly
Execution233ms
Transfer156 KB
Unused44%
Monthly Cost$3/mo
Google Tag Manager
Tag Manager
Costly
Execution221ms
Transfer164 KB
Unused41%
Monthly Cost$3/mo
use.fontawesome.com
Other
Optional
Execution181ms
Transfer611 KB
Monthly Cost$2/mo
Google Tag Manager
Tag Manager
Optional
Execution179ms
Transfer146 KB
Unused44%
Monthly Cost$2/mo
Google Tag Manager
Tag Manager
Optional
Execution168ms
Transfer145 KB
Unused44%
Monthly Cost$2/mo
Google Tag Manager
Tag Manager
Optional
Execution147ms
Transfer125 KB
Unused52%
Monthly Cost$2/mo
www.statcounter.com
Other
Optional
Execution107ms
Transfer17 KB
Monthly Cost$1/mo
Google Analytics
Analytics
Optional
Execution52ms
Transfer21 KB
Monthly Cost$1/mo
These scripts may cost more than they're worth
www.opengroup.org adds 1061ms and costs ~$14/month
Unattributable adds 536ms and costs ~$7/month
www.opengroup.org adds 384ms and costs ~$5/month
Google Tag Manager adds 293ms and costs ~$4/month
Google Tag Manager adds 244ms and costs ~$3/month
Google Tag Manager adds 233ms and costs ~$3/month
Google Tag Manager adds 221ms and costs ~$3/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.opengroup.org takes 1061ms 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 536ms 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.opengroup.org takes 384ms 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
67% of www.opengroup.org'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
Google Tag Manager takes 293ms 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 244ms 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 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
Google Tag Manager takes 221ms 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 Google Tag Manager'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.