Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.

SCORE

GRADE

FIX

REVIEW

PASS

INFO

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

Mobile Desktop

Performance

Accessibility

Best Practices

SEO

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

397 ms

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

1.94 s

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

0 ms

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

0.040

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

1.26 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.

2.00 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

9 PASS 3 REVIEW 1 FIX

Page Weight Budget

Action

11.7 MB transferred, 54 requests

FIX

11.7 MB transferred, 54 requests

Page weighs 12.9 MB (11.7 MB transferred)

Images are 1.8 MB — compress or use modern formats

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

Got: 1.8 MB

54 HTTP requests

Estimated 2.5 g CO2 per page load

11.7 MB transferred

54 requests

2.5 g CO2 per page load

Other 9.4 MiB 80%

Images 1.8 MiB 16%

JavaScript 235.7 KiB 2%

Fonts 147.6 KiB 1%

CSS 104.5 KiB 1%

HTML 27.2 KiB 0%

Other 13.3 KiB 0%

Other 953 B 0%

0 2.4 MB 4.9 MB

Over budget

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

Image Optimization

32 images, 0 KB saveable

REVIEW

32 images, 0 KB saveable

All images are well-optimized

32 images 1.8 MB

0 oversized -0 KB

13 legacy format

0 missing dimensions CLS risk

JS Bundles

4 scripts, 107 KB unused

REVIEW

4 scripts, 107 KB unused

https://www.googletagmanager.com/gtm.js?id=GTM-KTT...: 65 KB unused (49%)

Consider code splitting or tree shaking to reduce unused code.

https://iucn.org/sites/default/files/js/js_teBNjeQ...: 43 KB unused (61%)

Consider code splitting or tree shaking to reduce unused code.

Total unused JavaScript: 107 KB

107 KB unused JavaScript

Downloaded but never executed on this page.

Script	Size	Unused	Minified	Party
https://www.googletagmanager.com/gtm.js?id=GTM-KTTKSGS	132 KB	65 KB (49%)	✓	3rd
https://iucn.org/sites/default/files/js/js_teBNjeQ8bqfB9J0r4eyChJ08HtpnWlXUt9rnjJRdTSc.js?scope=footer&delta=0&language=en&theme=iucn_revamp&include=eJx1j4FqxSAMRX9In58kUdPW1RpJYt_e36920G2PDiQczoV4EyCuXul4zYUf9h9iApGKMjQfgDmTmwsFKFb0VXKdTSRGl7g3KI_E1EJXpWoSKBR4IbuAC-yZWEzusXr8zNqo9eYushI5N_3OGXfY2vsvv6PB9miXo_zxG9buC9S5w4xmLcDkzmmOFaunMHWJoJmqexdGsGAc5GUBPlpfwp4iGekNecqyuIvunF9oR85VseptLhuUchyMWO_zQdKD_Jc2knx2fqLfcIZxtpuIt8cT7RB2GDsxjRLpC96lva8	71 KB	43 KB (61%)	✓	1st
https://iucn.org/libraries/klaro/dist/klaro-no-translations-no-css.js?tduwtt	20 KB	—	✓	1st
https://iucn.org/cdn-cgi/challenge-platform/h/b/scripts/jsd/0b8fb825cb67/main.js?	12 KB	—	✓	1st

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

Page Weight Inventory

Action

54 resources · 11.7 MB · 107 KB savings available

REVIEW

54 resources · 11.7 MB · 107 KB savings available

Page weight 10.7 MB over 1MB target

Got: 11.7 MB Expected: ≤ 1 MB

~107 KB of savings available

8 third-party resources (1% of weight)

5 resources over 200KB

54 resources · 11.7 MiB · 8 third-party 10.7 MiB over 1MB target

Media 80% · 9.4 MiB

Image 16% · 1.8 MiB

JavaScript 2% · 235.7 KiB

Font 1% · 147.6 KiB

CSS 1% · 104.5 KiB

Document 0% · 27.2 KiB

Other 0% · 1.1 KiB

~107.3 KiB of savings available

Remove unused JavaScript: 107.3 KiB

#	Resource	Type	Size	Cache	Unused	3rd party	Issues

54 resources			11.7 MiB

A+

Third-Party Impact

1% third-party, 0 ms blocking

PASS

1% third-party, 0 ms blocking

Third-party code accounts for 1% of page weight (132.4 KiB of 11.7 MiB)

Third-party blocking time is low (0 ms)

99%

First-party Third-party

A+

Text Compression

All text resources are compressed

PASS

All text resources are compressed

All text resources are properly compressed.

A+

JS Execution Cost

408ms total JS execution

PASS

408ms total JS execution

Unattributable: 134ms CPU time

https://iucn.org/: 110ms CPU time

https://iucn.org/sites/default/files/js/js_teBNjeQ...: 105ms CPU time

https://iucn.org/cdn-cgi/challenge-platform/script...: 60ms CPU time

Third-party scripts: 134ms (33% of total)

Main Thread Breakdown

Script Evaluation 38% Other 31% Style & Layout 19% Parse HTML & CSS 4% Script Parsing & Compilation 4% Rendering 3%

Script	Total	Scripting	Parse/Compile	Party
Unattributable	134ms	3ms	0ms	3rd
https://iucn.org/	110ms	7ms	1ms	1st
https://iucn.org/sites/default/files/js/js_teBNjeQ8bqfB9J0r4eyChJ08HtpnWlXUt9rnjJRdTSc.js?scope=footer&delta=0&language=en&theme=iucn_revamp&include=eJx1j4FqxSAMRX9In58kUdPW1RpJYt_e36920G2PDiQczoV4EyCuXul4zYUf9h9iApGKMjQfgDmTmwsFKFb0VXKdTSRGl7g3KI_E1EJXpWoSKBR4IbuAC-yZWEzusXr8zNqo9eYushI5N_3OGXfY2vsvv6PB9miXo_zxG9buC9S5w4xmLcDkzmmOFaunMHWJoJmqexdGsGAc5GUBPlpfwp4iGekNecqyuIvunF9oR85VseptLhuUchyMWO_zQdKD_Jc2knx2fqLfcIZxtpuIt8cT7RB2GDsxjRLpC96lva8	105ms	79ms	5ms	1st
https://iucn.org/cdn-cgi/challenge-platform/scripts/jsd/main.js	60ms	58ms	1ms	1st

A+

Font Loading

5 fonts (148 KB)

PASS

5 fonts (148 KB)

5 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

148 KB total

Render-blocking

of 5

Dominant font-display

swap

Most common across fonts

Font loading timeline

Transfer FOIT (block) FOUT (swap)

HelveticaNeueLTStd-Roma... woff2 swap

Size 14 KB

Load time 80 ms

Start 283 ms