Skip to content
https://www.cnn.com

Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
72
GRADE
C
FIX
4
REVIEW
2
PASS
8
INFO
2

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
32
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
96
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
77
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
85
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

5.80 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

9.90 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

2.11 s

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.000

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

6.14 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

45.24 s

Page Load Progression

375 ms
750 ms
1.1 s
1.5 s
1.9 s
2.2 s
2.6 s
3.0 s
Checks
16
8 PASS 2 REVIEW 4 FIX
F
Page Weight Budget
Action
10.0 MB transferred, 153 requests
FIX
10.0 MB transferred, 153 requests
Critical::
Page weighs 20.9 MB (10.0 MB transferred)
Warning::
JavaScript is 4.2 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 4.2 MB
Warning::
Images are 4.0 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 4.0 MB
Info::
Fonts are 378 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 378 KB
Warning::
153 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 2.1 g CO2 per page load
10.0 MB / 2.4 MB budget
10.0 MB transferred
153 requests
2.1 g CO2 per page load
JavaScript 4.2 MiB 42%
Images 4.0 MiB 40%
Other 778.9 KiB 8%
HTML 506.3 KiB 5%
Fonts 378.5 KiB 4%
Other 78.5 KiB 1%
CSS 39.8 KiB 0%
Other 9.3 KiB 0%
Other 7.3 KiB 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Over budget

Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.

Why this matters

JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.

Source: web.dev

Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.

Why this matters

Image bandwidth is high — modern formats (WebP/AVIF) and resizing typically cut it 50%+.

Source: web.dev

Subset fonts to include only used characters, or switch to system font stacks.

Why this matters

Font payload is large — subset to used glyphs only, or fall back to system fonts (zero load time).

Source: web.dev font loading

Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.

Why this matters

High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.

Source: web.dev

D
Third-Party Impact
Action
100% third-party, 0 ms blocking
FIX
100% third-party, 0 ms blocking
Warning::
Third-party code accounts for 100% of page weight (10.0 MiB of 10.0 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
JS Execution Cost
Action
7619ms total JS execution
FIX
7619ms total JS execution
Warning::
https://edition.cnn.com/: 2965ms CPU time
Warning::
Unattributable: 984ms CPU time
Warning::
https://registry.api.cnn.io/bundles/fave/boltPlaye...: 637ms CPU time
Warning::
https://edition.cnn.com/media/sites/js/bundles/cnn...: 502ms CPU time
Warning::
https://registry.api.cnn.io/bundles/fave/boltInsta...: 485ms CPU time
Warning::
Third-party scripts: 7619ms (100% of total)

Main Thread Breakdown

Script Evaluation 39% Other 20% Script Parsing & Compilation 16% Style & Layout 15% Parse HTML & CSS 6% Rendering 4%
ScriptTotalScriptingParse/CompileParty
https://edition.cnn.com/2965ms621ms271ms3rd
Unattributable984ms18ms0ms3rd
https://registry.api.cnn.io/bundles/fave/boltPlayer-b296f72a/boltPlayer637ms412ms212ms3rd
https://edition.cnn.com/media/sites/js/bundles/cnn-edition-adfuel-275d6f33a8b3e59631886f14a6ce5dda2ec37648bb4b63d7ab13f3449be68c3d.min.js502ms422ms78ms3rd
https://registry.api.cnn.io/bundles/fave/boltInstance-476be30d/boltInstance485ms427ms27ms3rd
https://cdn.tinypass.com/api/tinypass.min.js384ms204ms35ms3rd
https://registry.api.cnn.io/bundles/fave/ui-34be6e59/ui348ms83ms264ms3rd
https://registry.api.cnn.io/bundles/fave/latest-4.x/js256ms202ms39ms3rd
https://registry.api.cnn.io/bundles/fave/vendor-f9ea2c98/vendor221ms79ms97ms3rd
https://lightning.cnn.com/launch/7be62238e4c3/97fa00444124/launch-2878c87af5e3.min.js213ms144ms63ms3rd

Showing top 10 of 15 scripts

F
JS Bundles
Action
29 scripts, 1.4 MB unused
FIX
29 scripts, 1.4 MB unused
Warning::
https://registry.api.cnn.io/bundles/fave/boltPlaye...: 411 KB unused (67%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://registry.api.cnn.io/bundles/fave/ui-34be6e...: 268 KB unused (12%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://registry.api.cnn.io/bundles/fave/vendor-f9...: 233 KB unused (71%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://edition.cnn.com/media/sites/js/bundles/cnn...: 160 KB unused (74%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cdn.tinypass.com/api/tinypass.min.js: 83 KB unused (63%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 1.4 MB
1462 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://registry.api.cnn.io/bundles/fave/boltPlayer-b296f72a/boltPlayer618 KB411 KB (67%)✓3rd
https://registry.api.cnn.io/bundles/fave/ui-34be6e59/ui2310 KB268 KB (12%)✓3rd
https://registry.api.cnn.io/bundles/fave/vendor-f9ea2c98/vendor340 KB233 KB (71%)✓3rd
https://edition.cnn.com/media/sites/js/bundles/cnn-edition-adfuel-275d6f33a8b3e59631886f14a6ce5dda2ec37648bb4b63d7ab13f3449be68c3d.min.js216 KB160 KB (74%)✓3rd
https://cdn.tinypass.com/api/tinypass.min.js132 KB83 KB (63%)✓3rd
https://edition.cnn.com/wbdotp/scripttemplates/202601.2.0/otBannerSdk.js111 KB81 KB (74%)✓3rd
https://cdn.optimizely.com/public/125375509/s/landingprod.js122 KB69 KB (57%)✓3rd
https://registry.api.cnn.io/bundles/fave/latest-4.x/js116 KB44 KB (38%)✓3rd
https://registry.api.cnn.io/bundles/fave/boltInstance-476be30d/boltInstance75 KB41 KB (55%)✓3rd
https://edition.cnn.com/media/sites/js/bundles/cnn-edition-adfuel-body-1fce5e168fb1eed920bbf774431d749437de654c05f8f151917b9d00d0a7a702.min.js43 KB29 KB (67%)✓3rd

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

B
Image Optimization
85 images, 0 KB saveable
REVIEW
85 images, 0 KB saveable
Info::
All images are well-optimized
85 images 4.0 MB
0 oversized -0 KB
40 legacy format
0 missing dimensions CLS risk
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 (378 KB)
PASS
6 fonts (378 KB)
Info::
6 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

6

378 KB total

Render-blocking

0

of 6

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 2.0 s 4.0 s 6.0 s 8.0 s 10.0 s FCP 5.8 s LCP 9.9 shttps://edition.cnn.com/fonts/cnn/cnn_sans_display-bold-v1.woff2cnn_sans_display-bold-v... https://edition.cnn.com/fonts/cnn/cnn_sans_display-bold-v1.woff2 — 47.2 KiB — 0 ms — font-display: swaphttps://edition.cnn.com/fonts/cnn/cnn_sans_display-medium-v1.woff2cnn_sans_display-medium... https://edition.cnn.com/fonts/cnn/cnn_sans_display-medium-v1.woff2 — 46.4 KiB — 0 ms — font-display: swaphttps://edition.cnn.com/fonts/cnn/cnn_sans_display-v1.woff2cnn_sans_display-v1.woff2 https://edition.cnn.com/fonts/cnn/cnn_sans_display-v1.woff2 — 46.5 KiB — 0 ms — font-display: swaphttps://edition.cnn.com/fonts/cnn/noto_serif-v1.woff2noto_serif-v1.woff2 https://edition.cnn.com/fonts/cnn/noto_serif-v1.woff2 — 157.6 KiB — 0 ms — font-display: swaphttps://ix.cnn.io/static/fonts/latest/cnnsans-bold.woff2cnnsans-bold.woff2 https://ix.cnn.io/static/fonts/latest/cnnsans-bold.woff2 — 34.9 KiB — 0 ms — font-display: swaphttps://ix.cnn.io/static/fonts/latest/cnnsans-regular.woff2cnnsans-regular.woff2 https://ix.cnn.io/static/fonts/latest/cnnsans-regular.woff2 — 45.9 KiB — 0 ms — font-display: swap
cnn_sans_display-bold-v... woff2 swap
Size 47 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
cnn_sans_display-medium... woff2 swap
Size 46 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
cnn_sans_display-v1.woff2 woff2 swap
Size 46 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
noto_serif-v1.woff2 woff2 swap
Size 158 KB
Load time 0 ms
Start 0 ms
Risk FOUT — 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
cnnsans-bold.woff2 woff2 swap
Size 35 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
cnnsans-regular.woff2 woff2 swap
Size 46 KB
Load time 0 ms
Start 0 ms
Risk FOUT — 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)

Fixing the unchecked items could save ~79 KB and ~158 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
A
HTTP Caching
max-age=60 (1 minute)
PASS
max-age=60 (1 minute)
Info::
Cache-Control header is set
Got: max-age=60, public
Info::
Effective TTL: 1 minute (max-age=60)
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

max-age=60, public

DirectiveValueMeaning
max-age60Cache for 1 minute
public—Any cache may store this response
Effective TTL: 60 seconds
Network Waterfall
153 requests over 0ms
INFO

Performance analysis not available for this result.

Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
100% of JavaScript execution is third-party
First-party Third-party 7619ms · 4718KB · $101/mo
edition.cnn.com
Other
Costly
Execution 2965ms
Transfer 504 KB
Monthly Cost $39/mo
Unattributable
Other
Costly
Execution 984ms
Transfer 0 KB
Monthly Cost $13/mo
registry.api.cnn.io
Other
Costly
Execution 637ms
Transfer 618 KB
Unused 67%
Monthly Cost $8/mo
edition.cnn.com
Other
Costly
Execution 502ms
Transfer 216 KB
Unused 74%
Monthly Cost $7/mo
registry.api.cnn.io
Other
Costly
Execution 485ms
Transfer 75 KB
Unused 55%
Monthly Cost $6/mo
cdn.tinypass.com
Other
Costly
Execution 384ms
Transfer 132 KB
Unused 63%
Monthly Cost $5/mo
registry.api.cnn.io
Other
Costly
Execution 348ms
Transfer 2310 KB
Unused 12%
Monthly Cost $5/mo
registry.api.cnn.io
Other
Costly
Execution 256ms
Transfer 116 KB
Unused 38%
Monthly Cost $3/mo
registry.api.cnn.io
Other
Costly
Execution 221ms
Transfer 340 KB
Unused 71%
Monthly Cost $3/mo
lightning.cnn.com
Other
Costly
Execution 213ms
Transfer 74 KB
Monthly Cost $3/mo
Optimizely
A/B Testing
Optional
Execution 180ms
Transfer 122 KB
Unused 57%
Monthly Cost $2/mo
cdn.cxense.com
Other
Optional
Execution 166ms
Transfer 38 KB
Unused 58%
Monthly Cost $2/mo
edition.cnn.com
Other
Optional
Execution 128ms
Transfer 43 KB
Unused 67%
Monthly Cost $2/mo
edition.cnn.com
Other
Optional
Execution 80ms
Transfer 111 KB
Unused 74%
Monthly Cost $1/mo
edition.cnn.com
Other
Optional
Execution 70ms
Transfer 18 KB
Monthly Cost $1/mo

These scripts may cost more than they're worth

  • edition.cnn.com adds 2965ms and costs ~$39/month
  • Unattributable adds 984ms and costs ~$13/month
  • registry.api.cnn.io adds 637ms and costs ~$8/month
  • edition.cnn.com adds 502ms and costs ~$7/month
  • registry.api.cnn.io adds 485ms and costs ~$6/month
  • cdn.tinypass.com adds 384ms and costs ~$5/month
  • registry.api.cnn.io adds 348ms and costs ~$5/month
  • registry.api.cnn.io adds 256ms and costs ~$3/month
  • registry.api.cnn.io adds 221ms and costs ~$3/month
  • lightning.cnn.com adds 213ms 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

edition.cnn.com takes 2965ms 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 984ms 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

registry.api.cnn.io takes 637ms 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

67% of registry.api.cnn.io'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

edition.cnn.com takes 502ms 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

74% of edition.cnn.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

registry.api.cnn.io takes 485ms 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 registry.api.cnn.io'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.tinypass.com takes 384ms 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

63% of cdn.tinypass.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

registry.api.cnn.io 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

registry.api.cnn.io takes 256ms 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

registry.api.cnn.io takes 221ms 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 registry.api.cnn.io'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

lightning.cnn.com takes 213ms 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

57% of Optimizely'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

58% of cdn.cxense.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

67% of edition.cnn.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

74% of edition.cnn.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

How third-party costs are calculated

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

Send Feedback