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https://worldwildlife.org

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
86
GRADE
B
FIX
2
REVIEW
2
PASS
11
INFO
2

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

Mobile Desktop
57
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
99
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
92
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
92
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.

2.71 s

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

3.63 s

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

232 ms

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

0.988

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

3.12 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.

7.83 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
17
11 PASS 2 REVIEW 2 FIX
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 (1.0 MiB of 1.0 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
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
JS Execution Cost
Action
1543ms total JS execution
REVIEW
1543ms total JS execution
Warning::
https://www.worldwildlife.org/: 545ms CPU time
Warning::
Unattributable: 358ms CPU time
Warning::
https://cdn.cookielaw.org/scripttemplates/202512.1...: 271ms CPU time
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-PTT...: 269ms CPU time
Info::
https://www.worldwildlife.org/static/js/main.08aab...: 100ms CPU time
Warning::
Third-party scripts: 1543ms (100% of total)

Main Thread Breakdown

Script Evaluation 34% Other 24% Style & Layout 23% Script Parsing & Compilation 7% Rendering 6% Parse HTML & CSS 4%
ScriptTotalScriptingParse/CompileParty
https://www.worldwildlife.org/545ms11ms1ms3rd
Unattributable358ms95ms0ms3rd
https://cdn.cookielaw.org/scripttemplates/202512.1.0/otBannerSdk.js271ms171ms47ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-PTTJ3C2M269ms178ms47ms3rd
https://www.worldwildlife.org/static/js/main.08aab79dcfc6.js100ms39ms14ms3rd
C
JS Bundles
Action
6 scripts, 196 KB unused
REVIEW
6 scripts, 196 KB unused
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-PTT...: 83 KB unused (47%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cdn.cookielaw.org/scripttemplates/202512.1...: 68 KB unused (54%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.worldwildlife.org/static/js/main.08aab...: 45 KB unused (86%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 196 KB
196 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://www.googletagmanager.com/gtm.js?id=GTM-PTTJ3C2M177 KB83 KB (47%)✓3rd
https://cdn.cookielaw.org/scripttemplates/202512.1.0/otBannerSdk.js126 KB68 KB (54%)✓3rd
https://www.worldwildlife.org/static/js/main.08aab79dcfc6.js52 KB45 KB (86%)✓3rd
https://assets.worldwildlife.org/www-prd/misc/OneTrust/OtAutoBlock.js4 KB—✓3rd
https://cdn.cookielaw.org/scripttemplates/otSDKStub.js9 KB—✓3rd
https://challenges.cloudflare.com/turnstile/v0/b/0b8fb825cb67/api.js17 KB—✓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

A
Page Weight Budget
1.0 MB transferred, 28 requests
PASS
1.0 MB transferred, 28 requests
Info::
Page weighs 2.6 MB (1.0 MB transferred)
Info::
Fonts are 273 KB — consider subsetting or using system fonts
Subset fonts to include only used characters, or switch to system font stacks.
Got: 273 KB
Info::
28 HTTP requests
Info::
Estimated 0.21 g CO2 per page load
1.0 MB / 2.4 MB budget
1.0 MB transferred
28 requests
0.21 g CO2 per page load
JavaScript 386.3 KiB 37%
Fonts 273.3 KiB 27%
Images 234.9 KiB 23%
Other 64.5 KiB 6%
CSS 31.4 KiB 3%
HTML 26.0 KiB 3%
Other 9.2 KiB 1%
Other 2.7 KiB 0%
Other 2.2 KiB 0%
0 2.4 MB 4.9 MB
Under budget

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

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
Image Optimization
7 images, 0 KB saveable
PASS
7 images, 0 KB saveable
Info::
All images are well-optimized
7 images 235 KB
0 oversized -0 KB
3 legacy format
0 missing dimensions CLS risk
A+
Font Loading
1 fonts (273 KB)
PASS
1 fonts (273 KB)
Info::
1 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

1

273 KB total

Render-blocking

0

of 1

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 1.0 s 2.0 s 3.0 s FCP 2.7 s LCP 3.6 shttps://www.worldwildlife.org/static/fonts/OpenSans-VariableFont.65c46fe9fcc0.woff2OpenSans-VariableFont.6... https://www.worldwildlife.org/static/fonts/OpenSans-VariableFont.65c46fe9fcc0.woff2 — 273.3 KiB — 118 ms — font-display: swap
OpenSans-VariableFont.6... woff2 swap
Size 273 KB
Load time 118 ms
Start 406 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
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 ~137 KB and ~274 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
Page Weight Inventory
28 resources · 1.0 MB · 196 KB savings available
PASS
28 resources · 1.0 MB · 196 KB savings available
Warning::
Page weight 7 KB over 1MB target
Got: 1.0 MB Expected: ≤ 1 MB
Info::
~196 KB of savings available
Warning::
27 third-party resources (100% of weight)
Info::
1 resources over 200KB
28 resources · 1.0 MiB · 27 third-party 6.6 KiB over 1MB target
JavaScript 37% · 386.3 KiB
Font 27% · 273.3 KiB
Image 23% · 237.2 KiB
Other 6% · 62.5 KiB
CSS 3% · 36.1 KiB
Document 3% · 35.2 KiB

~196.1 KiB of savings available

Remove unused JavaScript: 196.1 KiB
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+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: Cloudflare

Network Waterfall
28 requests over 825ms
INFO
0 ms 1.0 s 2.0 s 3.0 s FCP 2.7 s LCP 3.6 shttps://worldwildlife.org// https://worldwildlife.org/ — 301 — 137 B — 73 ms — h2https://www.worldwildlife.org/www.worldwildlife.org/ https://www.worldwildlife.org/ — 200 — 26.0 KiB — 112 ms — h2https://assets.worldwildlife.org/www-prd/misc/OneTrust/OtAutoBlock.jsassets.worldwildlife.org/www-prd/mi... https://assets.worldwildlife.org/www-prd/misc/OneTrust/OtAutoBlock.js — 200 — 4.5 KiB — 121 ms — h3https://cdn.cookielaw.org/scripttemplates/otSDKStub.jscdn.cookielaw.org/scripttemplates/o... https://cdn.cookielaw.org/scripttemplates/otSDKStub.js — 200 — 9.1 KiB — 99 ms — h2https://www.worldwildlife.org/static/css/main.eba748cdc84a.csswww.worldwildlife.org/static/css/ma... https://www.worldwildlife.org/static/css/main.eba748cdc84a.css — 200 — 31.4 KiB — 57 ms — h2https://assets.worldwildlife.org/www-prd/images/shutterstock_23254842.b686c5e0.fill-768x660.format-webp.webpassets.worldwildlife.org/www-prd/im... https://assets.worldwildlife.org/www-prd/images/shutterstock_23254842.b686c5e0.fill-768x660.format-webp.webp — 200 — 93.0 KiB — 148 ms — h3https://www.worldwildlife.org/static/js/main.08aab79dcfc6.jswww.worldwildlife.org/static/js/mai... https://www.worldwildlife.org/static/js/main.08aab79dcfc6.js — 200 — 52.5 KiB — 68 ms — h2https://challenges.cloudflare.com/turnstile/v0/api.js?render=explicitchallenges.cloudflare.com/turnstile... https://challenges.cloudflare.com/turnstile/v0/api.js?render=explicit — 302 — 265 B — 72 ms — h3https://cdn.cookielaw.org/consent/44cb9dd3-352b-44e8-a68b-cfcab9ec6d54/44cb9dd3-352b-44e8-a68b-cfcab9ec6d54.jsoncdn.cookielaw.org/consent/44cb9dd3-... https://cdn.cookielaw.org/consent/44cb9dd3-352b-44e8-a68b-cfcab9ec6d54/44cb9dd3-352b-44e8-a68b-cfcab9ec6d54.json — 200 — 2.5 KiB — 78 ms — h2https://www.googletagmanager.com/gtm.js?id=GTM-PTTJ3C2Mwww.googletagmanager.com/gtm.js?id=... https://www.googletagmanager.com/gtm.js?id=GTM-PTTJ3C2M — 200 — 176.9 KiB — 153 ms — h2https://www.worldwildlife.org/site.webmanifestwww.worldwildlife.org/site.webmanif... https://www.worldwildlife.org/site.webmanifest — 403 — 4.6 KiB — 54 ms — h3data:image/svg+xml;utf8,<svg xmlns=%27http://www.w3.org/2000/svg%27 viewBox=%270 0 14 14%27 fill=%2…www.w3.org/2000/svg%27 viewBox=%270... data:image/svg+xml;utf8,<svg xmlns=%27http://www.w3.org/2000/svg%27 viewBox=%270 0 14 14%27 fill=%2… — 200 — 0 B — 0 ms — datahttps://www.worldwildlife.org/static/images/cssBackgrounds/panda.4c41703e5fd3.svgwww.worldwildlife.org/static/images... https://www.worldwildlife.org/static/images/cssBackgrounds/panda.4c41703e5fd3.svg — 200 — 2.3 KiB — 65 ms — h3https://assets.worldwildlife.org/www-prd/images/Medium_WW239231.2e16d0ba.fill-672x504.format-webp.webpassets.worldwildlife.org/www-prd/im... https://assets.worldwildlife.org/www-prd/images/Medium_WW239231.2e16d0ba.fill-672x504.format-webp.webp — 200 — 35.8 KiB — 34 ms — h3https://www.worldwildlife.org/static/fonts/OpenSans-VariableFont.65c46fe9fcc0.woff2www.worldwildlife.org/static/fonts/... https://www.worldwildlife.org/static/fonts/OpenSans-VariableFont.65c46fe9fcc0.woff2 — 200 — 273.3 KiB — 118 ms — h3https://challenges.cloudflare.com/turnstile/v0/b/0b8fb825cb67/api.jschallenges.cloudflare.com/turnstile... https://challenges.cloudflare.com/turnstile/v0/b/0b8fb825cb67/api.js — 200 — 17.3 KiB — 42 ms — h3https://geolocation.onetrust.com/cookieconsentpub/v1/geo/locationgeolocation.onetrust.com/cookiecons... https://geolocation.onetrust.com/cookieconsentpub/v1/geo/location — 200 — 281 B — 100 ms — h2https://cdn.cookielaw.org/scripttemplates/202512.1.0/otBannerSdk.jscdn.cookielaw.org/scripttemplates/2... https://cdn.cookielaw.org/scripttemplates/202512.1.0/otBannerSdk.js — 200 — 126.0 KiB — 54 ms — h2https://assets.worldwildlife.org/www-prd/images/_WW2155076.width-800.format-webp.webpassets.worldwildlife.org/www-prd/im... https://assets.worldwildlife.org/www-prd/images/_WW2155076.width-800.format-webp.webp — 200 — 82.1 KiB — 55 ms — h3https://www.worldwildlife.org/site.webmanifestwww.worldwildlife.org/site.webmanif... https://www.worldwildlife.org/site.webmanifest — 403 — 4.6 KiB — 33 ms — h3https://www.worldwildlife.org/favicon.icowww.worldwildlife.org/favicon.ico https://www.worldwildlife.org/favicon.ico — 200 — 1.8 KiB — 49 ms — h3https://cdn.cookielaw.org/consent/44cb9dd3-352b-44e8-a68b-cfcab9ec6d54/019b93fc-4c4d-78ad-b6cf-7c1d4958ea77/en.jsoncdn.cookielaw.org/consent/44cb9dd3-... https://cdn.cookielaw.org/consent/44cb9dd3-352b-44e8-a68b-cfcab9ec6d54/019b93fc-4c4d-78ad-b6cf-7c1d4958ea77/en.json — 200 — 42.7 KiB — 44 ms — h2https://cdn.cookielaw.org/scripttemplates/202512.1.0/assets/otFlat.jsoncdn.cookielaw.org/scripttemplates/2... https://cdn.cookielaw.org/scripttemplates/202512.1.0/assets/otFlat.json — 200 — 3.4 KiB — 29 ms — h2https://cdn.cookielaw.org/scripttemplates/202512.1.0/assets/v2/otPcCenter.jsoncdn.cookielaw.org/scripttemplates/2... https://cdn.cookielaw.org/scripttemplates/202512.1.0/assets/v2/otPcCenter.json — 200 — 13.3 KiB — 32 ms — h2https://cdn.cookielaw.org/scripttemplates/202512.1.0/assets/otCommonStyles.csscdn.cookielaw.org/scripttemplates/2... https://cdn.cookielaw.org/scripttemplates/202512.1.0/assets/otCommonStyles.css — 200 — 4.6 KiB — 31 ms — h2https://cdn.cookielaw.org/logos/static/ot_guard_logo.svgcdn.cookielaw.org/logos/static/ot_g... https://cdn.cookielaw.org/logos/static/ot_guard_logo.svg — 200 — 504 B — 29 ms — h2https://cdn.cookielaw.org/logos/static/ot_company_logo.pngcdn.cookielaw.org/logos/static/ot_c... https://cdn.cookielaw.org/logos/static/ot_company_logo.png — 200 — 19.1 KiB — 31 ms — h2https://cdn.cookielaw.org/logos/static/powered_by_logo.svgcdn.cookielaw.org/logos/static/powe... https://cdn.cookielaw.org/logos/static/powered_by_logo.svg — 200 — 2.6 KiB — 29 ms — h2
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-party 1543ms · 382KB · $20/mo
www.worldwildlife.org
Other
Costly
Execution 545ms
Transfer 26 KB
Monthly Cost $7/mo
Unattributable
Other
Costly
Execution 358ms
Transfer 0 KB
Monthly Cost $5/mo
OneTrust
Consent
Essential
Execution 271ms
Transfer 126 KB
Unused 54%
Monthly Cost $4/mo
Google Tag Manager
Tag Manager
Costly
Execution 269ms
Transfer 177 KB
Unused 47%
Monthly Cost $4/mo
www.worldwildlife.org
Other
Optional
Execution 100ms
Transfer 52 KB
Unused 86%
Monthly Cost $1/mo

These scripts may cost more than they're worth

  • www.worldwildlife.org adds 545ms and costs ~$7/month
  • Unattributable adds 358ms and costs ~$5/month
  • Google Tag Manager adds 269ms 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.worldwildlife.org takes 545ms 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 358ms 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

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

Google Tag Manager takes 269ms 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

86% of www.worldwildlife.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

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.

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