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
52 images, 0 KB saveable
REVIEW
52 images, 0 KB saveable
Warning::
!
https://img.nbc.com/files/2025-08/streamon_cta_2.p... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/2026-04/miniature-wife-l... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/2024-08/nbcsports-bay-ar... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/images/2019/4/16/Telemun... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/2025-12/huntingparty_s2-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/2026-04/web_dl_1.jpg?imp... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/images/2019/3/11/Bravo-L... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/2025-09/laworder_svu_s27... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/2024-11/nbcsportsnow_whi... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/2025-09/laworder_svu_s27... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/2025-12/huntingparty_s2-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/2024-08/nbcsports-philad... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/2024-08/nbcsports-califo... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/images/2023/1/05/NBC-Log... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/2026-04/nba_playoff_logo... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/2026-04/nba_25-26_blazer... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/2025-09/onechicago-2025-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/images/2019/4/25/Univers... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/2024-08/nbcsports-boston... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/2024-08/nbcsports_white_... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/2025-09/onechicago-2025-... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/2025-07/pck_attribution_... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
!
https://img.nbc.com/files/2026-04/nba_25-26_rocket... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
52images643 KB
0oversized-0 KB
28legacy format
23missing 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
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
7 fonts (233 KB)
PASS
7 fonts (233 KB)
Info::
i
7 font(s) use font-display: swap (FOUT risk but functional)
Web fonts
7
233 KB total
Render-blocking
0
of 7
Dominant font-display
swap
Most common across fonts
Font loading timeline
TransferFOIT (block)FOUT (swap)
AcuminPro_200.woff2woff2swap
Size45 KB
Load time73 ms
Start192 ms
RiskFOUT — text flashes from fallback to web font
AcuminPro_400.woff2woff2swap
Size46 KB
Load time73 ms
Start195 ms
RiskFOUT — text flashes from fallback to web font
AcuminPro_600.woff2woff2swap
Size47 KB
Load time75 ms
Start195 ms
RiskFOUT — text flashes from fallback to web font
AcuminProSemiCondensed_...woff2swap
Size46 KB
Load time81 ms
Start195 ms
RiskFOUT — text flashes from fallback to web font
MontserratRegular.woff2woff2swap
Size16 KB
Load time83 ms
Start196 ms
RiskFOUT — text flashes from fallback to web font
MontserratBold.woff2woff2swap
Size16 KB
Load time85 ms
Start196 ms
RiskFOUT — text flashes from fallback to web font
nbciconfont.woff2woff2swap
Size16 KB
Load time20 ms
Start432 ms
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
14 hints, 0 missing preconnects
PASS
14 hints, 0 missing preconnects
Info::
✓
Page uses 14 resource hint(s)
Current Resource Hints
preconnect
2
preload
10
dns-prefetch
2
prefetch—
14 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
172 requests over 4705ms
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-party11674ms · 1988KB · $202/mo
Script
Category
Execution
Transfer
Unused
Monthly Cost
Verdict
www.nbc.com
www.nbc.com
Other
3383ms
26 KB
—
$58/mo
Costly
www.nbc.com
www.nbc.com
Other
2711ms
622 KB
47%
$47/mo
Costly
www.nbc.com
www.nbc.com
Other
1361ms
58 KB
—
$24/mo
Costly
Unattributable
Unattributable
Other
1338ms
0 KB
—
$23/mo
Costly
securepubads.g.doubleclick.net
securepubads.g.doubleclick.net
Other
397ms
188 KB
68%
$7/mo
Costly
mps.nbcuni.com
mps.nbcuni.com
Other
350ms
63 KB
66%
$6/mo
Costly
assets.adobedtm.com
assets.adobedtm.com
Other
286ms
79 KB
59%
$5/mo
Costly
OneTrust
cdn.cookielaw.org
Consent
267ms
103 KB
54%
$5/mo
Essential
cdn.branch.io
cdn.branch.io
Other
246ms
23 KB
—
$4/mo
Costly
Google Tag Manager
www.googletagmanager.com
Tag Manager
233ms
85 KB
61%
$4/mo
Costly
www.nbc.com
www.nbc.com
Other
214ms
275 KB
36%
$4/mo
Costly
OneTrust
cdn.cookielaw.org
Consent
210ms
12 KB
—
$4/mo
Essential
s.go-mpulse.net
s.go-mpulse.net
Other
147ms
57 KB
55%
$3/mo
Optional
www.nbc.com
www.nbc.com
Other
116ms
131 KB
—
$2/mo
Optional
securepubads.g.doubleclick.net
securepubads.g.doubleclick.net
Other
95ms
34 KB
—
$2/mo
Optional
OneTrust
cdn.cookielaw.org
Consent
76ms
9 KB
—
$1/mo
Essential
entitlement.auth.adobe.com
entitlement.auth.adobe.com
Other
71ms
39 KB
—
$1/mo
Optional
accounts.google.com
accounts.google.com
Other
64ms
96 KB
72%
$1/mo
Optional
Google Tag Manager
www.googletagmanager.com
Tag Manager
59ms
85 KB
66%
$1/mo
Optional
Google Ads Conversion
www.googleadservices.com
Advertising
50ms
2 KB
—
$1/mo
Optional
www.nbc.com
Other
Costly
Execution3383ms
Transfer26 KB
Monthly Cost$58/mo
www.nbc.com
Other
Costly
Execution2711ms
Transfer622 KB
Unused47%
Monthly Cost$47/mo
www.nbc.com
Other
Costly
Execution1361ms
Transfer58 KB
Monthly Cost$24/mo
Unattributable
Other
Costly
Execution1338ms
Transfer0 KB
Monthly Cost$23/mo
securepubads.g.doubleclick.net
Other
Costly
Execution397ms
Transfer188 KB
Unused68%
Monthly Cost$7/mo
mps.nbcuni.com
Other
Costly
Execution350ms
Transfer63 KB
Unused66%
Monthly Cost$6/mo
assets.adobedtm.com
Other
Costly
Execution286ms
Transfer79 KB
Unused59%
Monthly Cost$5/mo
OneTrust
Consent
Essential
Execution267ms
Transfer103 KB
Unused54%
Monthly Cost$5/mo
cdn.branch.io
Other
Costly
Execution246ms
Transfer23 KB
Monthly Cost$4/mo
Google Tag Manager
Tag Manager
Costly
Execution233ms
Transfer85 KB
Unused61%
Monthly Cost$4/mo
www.nbc.com
Other
Costly
Execution214ms
Transfer275 KB
Unused36%
Monthly Cost$4/mo
OneTrust
Consent
Essential
Execution210ms
Transfer12 KB
Monthly Cost$4/mo
s.go-mpulse.net
Other
Optional
Execution147ms
Transfer57 KB
Unused55%
Monthly Cost$3/mo
www.nbc.com
Other
Optional
Execution116ms
Transfer131 KB
Monthly Cost$2/mo
securepubads.g.doubleclick.net
Other
Optional
Execution95ms
Transfer34 KB
Monthly Cost$2/mo
OneTrust
Consent
Essential
Execution76ms
Transfer9 KB
Monthly Cost$1/mo
entitlement.auth.adobe.com
Other
Optional
Execution71ms
Transfer39 KB
Monthly Cost$1/mo
accounts.google.com
Other
Optional
Execution64ms
Transfer96 KB
Unused72%
Monthly Cost$1/mo
Google Tag Manager
Tag Manager
Optional
Execution59ms
Transfer85 KB
Unused66%
Monthly Cost$1/mo
Google Ads Conversion
Advertising
Optional
Execution50ms
Transfer2 KB
Monthly Cost$1/mo
These scripts may cost more than they're worth
www.nbc.com adds 3383ms and costs ~$58/month
www.nbc.com adds 2711ms and costs ~$47/month
www.nbc.com adds 1361ms and costs ~$24/month
Unattributable adds 1338ms and costs ~$23/month
securepubads.g.doubleclick.net adds 397ms and costs ~$7/month
mps.nbcuni.com adds 350ms and costs ~$6/month
assets.adobedtm.com adds 286ms and costs ~$5/month
cdn.branch.io adds 246ms and costs ~$4/month
Google Tag Manager adds 233ms and costs ~$4/month
www.nbc.com adds 214ms and costs ~$4/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.nbc.com takes 3383ms 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.nbc.com takes 2711ms 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.nbc.com takes 1361ms 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 1338ms 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
securepubads.g.doubleclick.net takes 397ms 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
68% 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
mps.nbcuni.com takes 350ms 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
66% of mps.nbcuni.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
assets.adobedtm.com takes 286ms 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
59% of assets.adobedtm.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
54% of OneTrust'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
cdn.branch.io takes 246ms 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
61% 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
www.nbc.com takes 214ms 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
55% of s.go-mpulse.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
72% of accounts.google.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
66% 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.