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
19 images, 0 KB saveable
REVIEW
19 images, 0 KB saveable
Warning::
!
https://uhf.microsoft.com/images/microsoft/RE1Mu3b... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://visualstudio.microsoft.com/wp-content/uplo... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://visualstudio.microsoft.com/wp-content/uplo... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://visualstudio.microsoft.com/wp-content/uplo... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://visualstudio.microsoft.com/wp-content/uplo... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://visualstudio.microsoft.com/wp-content/uplo... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://visualstudio.microsoft.com/wp-content/uplo... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
19images2.5 MB
0oversized-0 KB
7legacy format
7missing 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
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
6 fonts (331 KB)
PASS
6 fonts (331 KB)
Info::
i
6 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
6
331 KB total
Render-blocking
0
of 6
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
segoeui-regular.woff2woff2swap
Size36 KB
Load time26 ms
Start664 ms
RiskFOUT — text flashes from fallback to web font
segoeui-regular.woff2woff2swap
Size36 KB
Load time29 ms
Start665 ms
RiskFOUT — text flashes from fallback to web font
segoeui-semibold.woff2woff2swap
Size32 KB
Load time33 ms
Start665 ms
RiskFOUT — text flashes from fallback to web font
segoeui-semibold.woff2woff2swap
Size32 KB
Load time37 ms
Start665 ms
RiskFOUT — text flashes from fallback to web font
vscom.ttfttfswap
Size2 KB
Load time38 ms
Start666 ms
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
woff;base64,d09GRgABAAA...woffswap
Size193 KB
Load time40 ms
Start852 ms
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
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 ~155 KB and ~310 ms
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
3 hints, 0 missing preconnects
PASS
3 hints, 0 missing preconnects
Info::
✓
Page uses 3 resource hint(s)
Current Resource Hints
preconnect
2
preload
1
dns-prefetch—
prefetch—
3 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
101 requests over 3663ms
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-party4297ms · 861KB · $25/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
visualstudio.microsoft.com
visualstudio.microsoft.com
Other
1136ms
173 KB
79%
$7/mo
Costly
Unattributable
Unattributable
Other
1027ms
0 KB
—
$6/mo
Costly
visualstudio.microsoft.com
visualstudio.microsoft.com
Other
851ms
53 KB
—
$5/mo
Costly
uhf.microsoft.com
uhf.microsoft.com
Other
356ms
38 KB
—
$2/mo
Costly
visualstudio.microsoft.com
visualstudio.microsoft.com
Other
236ms
31 KB
—
$1/mo
Costly
Microsoft Clarity
scripts.clarity.ms
Session Replay
234ms
26 KB
—
$1/mo
Costly
wcpstatic.microsoft.com
wcpstatic.microsoft.com
Other
146ms
274 KB
—
$1/mo
Optional
js.monitor.azure.com
js.monitor.azure.com
Other
129ms
60 KB
—
$1/mo
Optional
uhf.microsoft.com
uhf.microsoft.com
Other
68ms
112 KB
47%
$0/mo
Optional
visualstudio.microsoft.com
visualstudio.microsoft.com
Other
61ms
90 KB
—
$0/mo
Optional
visualstudio.microsoft.com
visualstudio.microsoft.com
Other
53ms
6 KB
—
$0/mo
Optional
visualstudio.microsoft.com
Other
Costly
Execution1136ms
Transfer173 KB
Unused79%
Monthly Cost$7/mo
Unattributable
Other
Costly
Execution1027ms
Transfer0 KB
Monthly Cost$6/mo
visualstudio.microsoft.com
Other
Costly
Execution851ms
Transfer53 KB
Monthly Cost$5/mo
uhf.microsoft.com
Other
Costly
Execution356ms
Transfer38 KB
Monthly Cost$2/mo
visualstudio.microsoft.com
Other
Costly
Execution236ms
Transfer31 KB
Monthly Cost$1/mo
Microsoft Clarity
Session Replay
Costly
Execution234ms
Transfer26 KB
Monthly Cost$1/mo
wcpstatic.microsoft.com
Other
Optional
Execution146ms
Transfer274 KB
Monthly Cost$1/mo
js.monitor.azure.com
Other
Optional
Execution129ms
Transfer60 KB
Monthly Cost$1/mo
uhf.microsoft.com
Other
Optional
Execution68ms
Transfer112 KB
Unused47%
Monthly Cost$0/mo
visualstudio.microsoft.com
Other
Optional
Execution61ms
Transfer90 KB
Monthly Cost$0/mo
visualstudio.microsoft.com
Other
Optional
Execution53ms
Transfer6 KB
Monthly Cost$0/mo
These scripts may cost more than they're worth
visualstudio.microsoft.com adds 1136ms and costs ~$7/month
Unattributable adds 1027ms and costs ~$6/month
visualstudio.microsoft.com adds 851ms and costs ~$5/month
uhf.microsoft.com adds 356ms and costs ~$2/month
visualstudio.microsoft.com adds 236ms and costs ~$1/month
Microsoft Clarity adds 234ms and costs ~$1/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
visualstudio.microsoft.com takes 1136ms 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
79% of visualstudio.microsoft.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
Unattributable takes 1027ms 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
visualstudio.microsoft.com takes 851ms 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
uhf.microsoft.com takes 356ms 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
visualstudio.microsoft.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
Microsoft Clarity takes 234ms 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.