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
34 images, 0 KB saveable
REVIEW
34 images, 0 KB saveable
Warning::
!
https://www.eurekalert.org/images/uploads/wpi-stac... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.eurekalert.org/images/uploads/parkinso... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.eurekalert.org/images/uploads/spj24-eu... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.eurekalert.org/images/uploads/climate_... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.eurekalert.org/images/uploads/nih-mast... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.eurekalert.org/images/logo-2x.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.eurekalert.org/images/brand.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.eurekalert.org/images/uploads/acs-1814... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.eurekalert.org/images/uploads/nutritio... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.eurekalert.org/images/uploads/cancer_r... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://mediasvc.eurekalert.org/Api/v1/Multimedia/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.eurekalert.org/images/uploads/acs-chem... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.eurekalert.org/images/uploads/nsf-home... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.eurekalert.org/images/logo-footer.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.eurekalert.org/images/uploads/marine_s... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.eurekalert.org/images/uploads/doe-6167... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://mediasvc.eurekalert.org/Api/v1/Multimedia/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://mediasvc.eurekalert.org/Api/v1/Multimedia/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://mediasvc.eurekalert.org/Api/v1/Multimedia/... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.eurekalert.org/images/uploads/square-l... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://www.eurekalert.org/images/uploads/300x250-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
34images1.0 MB
0oversized-0 KB
16legacy format
21missing 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
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 (141 KB)
PASS
3 fonts (141 KB)
Info::
i
3 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
3
141 KB total
Render-blocking
0
of 3
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
fontawesome-webfont.woff2woff2swap
Size76 KB
Load time75 ms
Start3.2 s
RiskFOUT — text flashes from fallback to web font
memvYaGs126MiZpBA-UvWbX...woff2swap
Size42 KB
Load time37 ms
Start3.2 s
RiskFOUT — text flashes from fallback to web font
glyphicons-halflings-re...woffswap
Size23 KB
Load time261 ms
Start3.2 s
RiskFOUT — text flashes from fallback to web font
Convert to woff2 for ~30% smaller file size
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 ~7 KB and ~14 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
102 requests over 5670ms
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-party8314ms · 6948KB · $110/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
www.eurekalert.org
www.eurekalert.org
Other
2237ms
5361 KB
71%
$30/mo
Costly
securepubads.g.doubleclick.net
securepubads.g.doubleclick.net
Other
1317ms
187 KB
56%
$17/mo
Costly
www.eurekalert.org
www.eurekalert.org
Other
1181ms
101 KB
—
$16/mo
Costly
Unattributable
Unattributable
Other
797ms
0 KB
—
$11/mo
Costly
pagead2.googlesyndication.com
pagead2.googlesyndication.com
Other
534ms
0 KB
43%
$7/mo
Costly
assets.adobedtm.com
assets.adobedtm.com
Other
392ms
98 KB
31%
$5/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
348ms
145 KB
43%
$5/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
330ms
172 KB
40%
$4/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
275ms
138 KB
41%
$4/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
272ms
138 KB
45%
$4/mo
Costly
www.eurekalert.org
www.eurekalert.org
Other
229ms
414 KB
87%
$3/mo
Costly
Facebook Pixel
connect.facebook.net
Advertising
115ms
97 KB
36%
$2/mo
Optional
js-agent.newrelic.com
js-agent.newrelic.com
Other
111ms
30 KB
—
$1/mo
Optional
Facebook Pixel
connect.facebook.net
Advertising
99ms
33 KB
—
$1/mo
Optional
www.googletagservices.com
www.googletagservices.com
Other
76ms
34 KB
—
$1/mo
Optional
www.eurekalert.org
Other
Costly
Execution2237ms
Transfer5361 KB
Unused71%
Monthly Cost$30/mo
securepubads.g.doubleclick.net
Other
Costly
Execution1317ms
Transfer187 KB
Unused56%
Monthly Cost$17/mo
www.eurekalert.org
Other
Costly
Execution1181ms
Transfer101 KB
Monthly Cost$16/mo
Unattributable
Other
Costly
Execution797ms
Transfer0 KB
Monthly Cost$11/mo
pagead2.googlesyndication.com
Other
Costly
Execution534ms
Transfer0 KB
Unused43%
Monthly Cost$7/mo
assets.adobedtm.com
Other
Costly
Execution392ms
Transfer98 KB
Unused31%
Monthly Cost$5/mo
Google Tag Manager
Tag Manager
Costly
Execution348ms
Transfer145 KB
Unused43%
Monthly Cost$5/mo
Google Tag Manager
Tag Manager
Costly
Execution330ms
Transfer172 KB
Unused40%
Monthly Cost$4/mo
Google Tag Manager
Tag Manager
Costly
Execution275ms
Transfer138 KB
Unused41%
Monthly Cost$4/mo
Google Tag Manager
Tag Manager
Costly
Execution272ms
Transfer138 KB
Unused45%
Monthly Cost$4/mo
www.eurekalert.org
Other
Costly
Execution229ms
Transfer414 KB
Unused87%
Monthly Cost$3/mo
Facebook Pixel
Advertising
Optional
Execution115ms
Transfer97 KB
Unused36%
Monthly Cost$2/mo
js-agent.newrelic.com
Other
Optional
Execution111ms
Transfer30 KB
Monthly Cost$1/mo
Facebook Pixel
Advertising
Optional
Execution99ms
Transfer33 KB
Monthly Cost$1/mo
www.googletagservices.com
Other
Optional
Execution76ms
Transfer34 KB
Monthly Cost$1/mo
These scripts may cost more than they're worth
www.eurekalert.org adds 2237ms and costs ~$30/month
securepubads.g.doubleclick.net adds 1317ms and costs ~$17/month
www.eurekalert.org adds 1181ms and costs ~$16/month
Unattributable adds 797ms and costs ~$11/month
pagead2.googlesyndication.com adds 534ms and costs ~$7/month
assets.adobedtm.com adds 392ms and costs ~$5/month
Google Tag Manager adds 348ms and costs ~$5/month
Google Tag Manager adds 330ms and costs ~$4/month
Google Tag Manager adds 275ms and costs ~$4/month
Google Tag Manager adds 272ms and costs ~$4/month
www.eurekalert.org adds 229ms 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.eurekalert.org takes 2237ms 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
71% of www.eurekalert.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
securepubads.g.doubleclick.net takes 1317ms 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
56% of securepubads.g.doubleclick.net'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.eurekalert.org takes 1181ms 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 797ms 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
pagead2.googlesyndication.com takes 534ms 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
assets.adobedtm.com takes 392ms 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 348ms 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 330ms 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 275ms 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 272ms 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.eurekalert.org takes 229ms 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
87% of www.eurekalert.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.