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::
!
is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.faa.gov/themes/custom/dot_cms/images/a... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.faa.gov/themes/custom/faa/images/logo-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.faa.gov/sites/faa.gov/files/styles/faa... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
14images853 KB
0oversized-0 KB
11legacy format
4missing dimensionsCLS risk
Set explicit width and height to prevent CLS.
Why this matters
Performance issues directly impact user engagement and conversion rates.
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
9 fonts (545 KB)
PASS
9 fonts (545 KB)
Info::
i
9 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
9
545 KB total
Render-blocking
0
of 9
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
6xK3dSBYKcSV-LCoeQqfX1R...woff2swap
Size15 KB
Load time36 ms
Start1.1 s
RiskFOUT — text flashes from fallback to web font
fa-solid-900.woff2woff2swap
Size153 KB
Load time68 ms
Start1.1 s
RiskFOUT — text flashes from fallback to web font
Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
S6uyw4BMUTPHjx4wXiWtFCc...woff2swap
Size14 KB
Load time42 ms
Start1.1 s
RiskFOUT — text flashes from fallback to web font
Lato-Semibold.woff2woff2swap
Size180 KB
Load time343 ms
Start1.1 s
RiskFOUT — text flashes from fallback to web font
Subset this font — over 100 KB suggests Latin Extended or full glyph coverage that most pages don't need
6xKydSBYKcSV-LCoeQqfX1R...woff2swap
Size14 KB
Load time60 ms
Start1.1 s
RiskFOUT — text flashes from fallback to web font
6xKydSBYKcSV-LCoeQqfX1R...woff2swap
Size15 KB
Load time42 ms
Start1.1 s
RiskFOUT — text flashes from fallback to web font
fa-regular-400.woff2woff2swap
Size25 KB
Load time64 ms
Start1.1 s
RiskFOUT — text flashes from fallback to web font
S6u9w4BMUTPHh7USSwiPGQ3...woff2swap
Size14 KB
Load time56 ms
Start1.1 s
RiskFOUT — text flashes from fallback to web font
fa-brands-400.woff2woff2swap
Size115 KB
Load time73 ms
Start1.1 s
RiskFOUT — text flashes from fallback to web font
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 ~224 KB and ~448 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
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
69 requests over 2057ms
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-party3151ms · 1284KB · $42/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
www.faa.gov
www.faa.gov
Other
490ms
20 KB
—
$6/mo
Costly
Unattributable
Unattributable
Other
482ms
0 KB
—
$6/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
276ms
147 KB
42%
$4/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
252ms
153 KB
42%
$3/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
236ms
157 KB
42%
$3/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
235ms
156 KB
41%
$3/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
209ms
125 KB
51%
$3/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
207ms
156 KB
43%
$3/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
188ms
117 KB
53%
$2/mo
Optional
www.faa.gov
www.faa.gov
Other
157ms
32 KB
—
$2/mo
Optional
Google Tag Manager
www.googletagmanager.com
Tag Manager
119ms
147 KB
72%
$2/mo
Optional
www.faa.gov
www.faa.gov
Other
114ms
9 KB
—
$2/mo
Optional
dap.digitalgov.gov
dap.digitalgov.gov
Other
80ms
5 KB
—
$1/mo
Optional
www.faa.gov
www.faa.gov
Other
53ms
39 KB
74%
$1/mo
Optional
Google Analytics
www.google-analytics.com
Analytics
53ms
21 KB
—
$1/mo
Optional
www.faa.gov
Other
Costly
Execution490ms
Transfer20 KB
Monthly Cost$6/mo
Unattributable
Other
Costly
Execution482ms
Transfer0 KB
Monthly Cost$6/mo
Google Tag Manager
Tag Manager
Costly
Execution276ms
Transfer147 KB
Unused42%
Monthly Cost$4/mo
Google Tag Manager
Tag Manager
Costly
Execution252ms
Transfer153 KB
Unused42%
Monthly Cost$3/mo
Google Tag Manager
Tag Manager
Costly
Execution236ms
Transfer157 KB
Unused42%
Monthly Cost$3/mo
Google Tag Manager
Tag Manager
Costly
Execution235ms
Transfer156 KB
Unused41%
Monthly Cost$3/mo
Google Tag Manager
Tag Manager
Costly
Execution209ms
Transfer125 KB
Unused51%
Monthly Cost$3/mo
Google Tag Manager
Tag Manager
Costly
Execution207ms
Transfer156 KB
Unused43%
Monthly Cost$3/mo
Google Tag Manager
Tag Manager
Optional
Execution188ms
Transfer117 KB
Unused53%
Monthly Cost$2/mo
www.faa.gov
Other
Optional
Execution157ms
Transfer32 KB
Monthly Cost$2/mo
Google Tag Manager
Tag Manager
Optional
Execution119ms
Transfer147 KB
Unused72%
Monthly Cost$2/mo
www.faa.gov
Other
Optional
Execution114ms
Transfer9 KB
Monthly Cost$2/mo
dap.digitalgov.gov
Other
Optional
Execution80ms
Transfer5 KB
Monthly Cost$1/mo
www.faa.gov
Other
Optional
Execution53ms
Transfer39 KB
Unused74%
Monthly Cost$1/mo
Google Analytics
Analytics
Optional
Execution53ms
Transfer21 KB
Monthly Cost$1/mo
These scripts may cost more than they're worth
www.faa.gov adds 490ms and costs ~$6/month
Unattributable adds 482ms and costs ~$6/month
Google Tag Manager adds 276ms and costs ~$4/month
Google Tag Manager adds 252ms and costs ~$3/month
Google Tag Manager adds 236ms and costs ~$3/month
Google Tag Manager adds 235ms and costs ~$3/month
Google Tag Manager adds 209ms and costs ~$3/month
Google Tag Manager adds 207ms 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.faa.gov takes 490ms 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 482ms 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 276ms 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 252ms 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 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
Google Tag Manager takes 235ms 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 209ms 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
51% 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
Google Tag Manager takes 207ms 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
53% 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
72% 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
74% of www.faa.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.