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
14 images, 0 KB saveable
REVIEW
14 images, 0 KB saveable
Warning::
!
https://www.gpo.gov/images/default-source/default-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.gpo.gov/images/default-source/other-im... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.gpo.gov/images/default-source/governme... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.gpo.gov/images/default-source/governme... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.gpo.gov/CustomResources/img/logo_text.... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.gpo.gov/images/default-source/other-im... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.gpo.gov/images/default-source/other-im... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.gpo.gov/images/default-source/governme... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
14images926 KB
0oversized-0 KB
12legacy 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
3 fonts (105 KB)
PASS
3 fonts (105 KB)
Info::
i
3 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
3
105 KB total
Render-blocking
0
of 3
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
jizDREVNn1dOx-zrZ2X3pZv...woff2swap
Size15 KB
Load time29 ms
Start4.2 s
RiskFOUT — text flashes from fallback to web font
glyphicons-halflings-re...woff2swap
Size21 KB
Load time213 ms
Start4.2 s
RiskFOUT — text flashes from fallback to web font
fontawesome-webfont.woff2woff2swap
Size70 KB
Load time65 ms
Start4.2 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
63 requests over 5830ms
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-party2578ms · 1960KB · $15/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
www.gpo.gov
www.gpo.gov
Other
1174ms
1451 KB
79%
$7/mo
Costly
www.gpo.gov
www.gpo.gov
Other
321ms
0 KB
—
$2/mo
Costly
Unattributable
Unattributable
Other
318ms
0 KB
—
$2/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
278ms
159 KB
40%
$2/mo
Costly
www.gpo.gov
www.gpo.gov
Other
200ms
42 KB
—
$1/mo
Optional
Google Tag Manager
www.googletagmanager.com
Tag Manager
133ms
112 KB
62%
$1/mo
Optional
www.gpo.gov
www.gpo.gov
Other
86ms
36 KB
—
$0/mo
Optional
Google Tag Manager
www.googletagmanager.com
Tag Manager
68ms
159 KB
69%
$0/mo
Optional
www.gpo.gov
Other
Costly
Execution1174ms
Transfer1451 KB
Unused79%
Monthly Cost$7/mo
www.gpo.gov
Other
Costly
Execution321ms
Transfer0 KB
Monthly Cost$2/mo
Unattributable
Other
Costly
Execution318ms
Transfer0 KB
Monthly Cost$2/mo
Google Tag Manager
Tag Manager
Costly
Execution278ms
Transfer159 KB
Unused40%
Monthly Cost$2/mo
www.gpo.gov
Other
Optional
Execution200ms
Transfer42 KB
Monthly Cost$1/mo
Google Tag Manager
Tag Manager
Optional
Execution133ms
Transfer112 KB
Unused62%
Monthly Cost$1/mo
www.gpo.gov
Other
Optional
Execution86ms
Transfer36 KB
Monthly Cost$0/mo
Google Tag Manager
Tag Manager
Optional
Execution68ms
Transfer159 KB
Unused69%
Monthly Cost$0/mo
These scripts may cost more than they're worth
www.gpo.gov adds 1174ms and costs ~$7/month
www.gpo.gov adds 321ms and costs ~$2/month
Unattributable adds 318ms and costs ~$2/month
Google Tag Manager adds 278ms 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.gpo.gov takes 1174ms 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 www.gpo.gov'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.gpo.gov takes 321ms 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 318ms 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 278ms 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
62% 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.
Source: web.dev
69% 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.