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Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
74
GRADE
C
FIX
4
REVIEW
3
PASS
8
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.
91
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
81
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.

2.60 s

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

27.67 s

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

313 ms

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.

7.26 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.

29.44 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
8 PASS 3 REVIEW 4 FIX
F
Page Weight Budget
Action
10.7 MB transferred, 41 requests
FIX
10.7 MB transferred, 41 requests
Critical::
Page weighs 12.6 MB (10.7 MB transferred)
Warning::
Images are 9.9 MB — compress or use modern formats
Convert images to WebP/AVIF and resize to display dimensions to reduce transfer size.
Got: 9.9 MB
Warning::
JavaScript is 638 KB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 638 KB
Info::
41 HTTP requests
Info::
Estimated 2.2 g CO2 per page load
10.7 MB / 2.4 MB budget
10.7 MB transferred
41 requests
2.2 g CO2 per page load
Images 9.9 MiB 93%
JavaScript 637.6 KiB 6%
Fonts 77.4 KiB 1%
CSS 66.6 KiB 1%
HTML 22.7 KiB 0%
Other 3.3 KiB 0%
Other 1.3 KiB 0%
Other 21 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

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

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 (10.7 MiB of 10.7 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
D
JS Bundles
Action
11 scripts, 353 KB unused
FIX
11 scripts, 353 KB unused
Warning::
https://js.stripe.com/v3/: 160 KB unused (73%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.iop.org/sites/default/files/js/js_Ki6p...: 125 KB unused (59%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtm.js?id=GTM-53N...: 69 KB unused (43%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 353 KB
353 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://js.stripe.com/v3/220 KB160 KB (73%)✓3rd
https://www.iop.org/sites/default/files/js/js_Ki6p2MbdPgNqjhHP0F6p7XrB0gv4Lc_5vPSzXWBUDfE.js?scope=footer&delta=0&language=en&theme=iop_theme&include=eJxtjEsOwzAIRC_kliMh3EwdV8RENs2np2_k7KJsHrwBTYQ7KmObrWHgd9ZDGyUUVNEQ788NipezqHKxghBVfjvFbE_5yBaSWVKwS6J04Oo3T1PINvMgLio7KmFB8Z75iAmU1KLo45tD85pn0DnCkrE26jxb-8pttJUnq6CL_wEIVF3V211 KB125 KB (59%)✓3rd
https://www.googletagmanager.com/gtm.js?id=GTM-53NVWC3161 KB69 KB (43%)✓3rd
https://www.iop.org/sites/default/files/js/js_b6LZj6c1gz5idt2o-8QkVwsK-lkMhFq2B74gzi7XeTc.js?scope=header&delta=0&language=en&theme=iop_theme&include=eJxtjEsOwzAIRC_kliMh3EwdV8RENs2np2_k7KJsHrwBTYQ7KmObrWHgd9ZDGyUUVNEQ788NipezqHKxghBVfjvFbE_5yBaSWVKwS6J04Oo3T1PINvMgLio7KmFB8Z75iAmU1KLo45tD85pn0DnCkrE26jxb-8pttJUnq6CL_wEIVF3V1 KB—✓3rd
https://www.iop.org/modules/contrib/google_tag/js/gtag.js?tdi04s1 KB—✓3rd
https://www.iop.org/modules/contrib/google_tag/js/gtm.js?tdi04s1 KB—✓3rd
https://www.iop.org/sites/default/files/js/js_EB8HHnoaRzJDiYTotyhw_tMrAF480yAEVjnosKdN8fE.js?scope=footer&delta=2&language=en&theme=iop_theme&include=eJxtjEsOwzAIRC_kliMh3EwdV8RENs2np2_k7KJsHrwBTYQ7KmObrWHgd9ZDGyUUVNEQ788NipezqHKxghBVfjvFbE_5yBaSWVKwS6J04Oo3T1PINvMgLio7KmFB8Z75iAmU1KLo45tD85pn0DnCkrE26jxb-8pttJUnq6CL_wEIVF3V13 KB—✓3rd
https://www.iop.org/cdn-cgi/challenge-platform/h/b/scripts/jsd/0b8fb825cb67/main.js?13 KB—✓3rd
https://cdn.cookielaw.org/scripttemplates/otSDKStub.js?did=fff4ce83-f4c5-4f6d-8d8a-91e4dd5e04a30 KB—✓3rd
https://js.stripe.com/v3/fingerprinted/js/m-outer-15a2b40a058ddff1cffdb63779fe3de1.js0 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

D
Page Weight Inventory
Action
41 resources · 10.7 MB · 353 KB savings available
FIX
41 resources · 10.7 MB · 353 KB savings available
Warning::
Page weight 9.7 MB over 1MB target
Got: 10.7 MB Expected: ≤ 1 MB
Info::
~353 KB of savings available
Warning::
40 third-party resources (100% of weight)
Info::
12 resources over 200KB
41 resources · 10.7 MiB · 40 third-party 9.7 MiB over 1MB target
Image 93% · 9.9 MiB
JavaScript 6% · 637.6 KiB
Font 1% · 77.4 KiB
CSS 1% · 66.6 KiB
Document 0% · 23.0 KiB
Other 0% · 1.5 KiB

~353.5 KiB of savings available

Remove unused JavaScript: 353.5 KiB
B
Image Optimization
15 images, 0 KB saveable
REVIEW
15 images, 0 KB saveable
Info::
All images are well-optimized
15 images 9.9 MB
0 oversized -0 KB
15 legacy format
0 missing dimensions CLS risk
C
JS Execution Cost
Action
1952ms total JS execution
REVIEW
1952ms total JS execution
Warning::
https://www.iop.org/: 468ms CPU time
Warning::
https://www.iop.org/sites/default/files/js/js_Ki6p...: 425ms CPU time
Warning::
Unattributable: 392ms CPU time
Info::
https://js.stripe.com/v3/: 240ms CPU time
Info::
https://www.googletagmanager.com/gtm.js?id=GTM-53N...: 221ms CPU time
Warning::
Third-party scripts: 1952ms (100% of total)

Main Thread Breakdown

Script Evaluation 45% Other 24% Style & Layout 14% Script Parsing & Compilation 9%
ScriptTotalScriptingParse/CompileParty
https://www.iop.org/468ms50ms2ms3rd
https://www.iop.org/sites/default/files/js/js_Ki6p2MbdPgNqjhHP0F6p7XrB0gv4Lc_5vPSzXWBUDfE.js?scope=footer&delta=0&language=en&theme=iop_theme&include=eJxtjEsOwzAIRC_kliMh3EwdV8RENs2np2_k7KJsHrwBTYQ7KmObrWHgd9ZDGyUUVNEQ788NipezqHKxghBVfjvFbE_5yBaSWVKwS6J04Oo3T1PINvMgLio7KmFB8Z75iAmU1KLo45tD85pn0DnCkrE26jxb-8pttJUnq6CL_wEIVF3V425ms314ms52ms3rd
Unattributable392ms6ms0ms3rd
https://js.stripe.com/v3/240ms152ms85ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-53NVWC3221ms174ms42ms3rd
https://www.iop.org/cdn-cgi/challenge-platform/scripts/jsd/main.js207ms197ms3ms3rd
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
4 fonts (77 KB)
PASS
4 fonts (77 KB)
Info::
4 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

4

77 KB total

Render-blocking

0

of 4

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 12.0 s 14.0 s 16.0 s 18.0 s 20.0 s 22.0 s 24.0 s 26.0 s 28.0 s FCP 2.6 s LCP 27.7 shttps://www.iop.org/themes/custom/iop_theme/build/fonts/FranklinGothicURW-Boo.woff2FranklinGothicURW-Boo.w... https://www.iop.org/themes/custom/iop_theme/build/fonts/FranklinGothicURW-Boo.woff2 — 14.1 KiB — 51 ms — font-display: swaphttps://www.iop.org/themes/custom/iop_theme/build/fonts/FranklinGothicURWCon-Dem.woff2FranklinGothicURWCon-De... https://www.iop.org/themes/custom/iop_theme/build/fonts/FranklinGothicURWCon-Dem.woff2 — 13.5 KiB — 59 ms — font-display: swaphttps://www.iop.org/themes/custom/iop_theme/build/fonts/icomoon.wofficomoon.woff https://www.iop.org/themes/custom/iop_theme/build/fonts/icomoon.woff — 35.8 KiB — 51 ms — font-display: swaphttps://www.iop.org/themes/custom/iop_theme/build/fonts/FranklinGothicURW-Dem.woff2FranklinGothicURW-Dem.w... https://www.iop.org/themes/custom/iop_theme/build/fonts/FranklinGothicURW-Dem.woff2 — 14.0 KiB — 51 ms — font-display: swap
FranklinGothicURW-Boo.w... woff2 swap
Size 14 KB
Load time 51 ms
Start 433 ms
Risk FOUT — text flashes from fallback to web font
FranklinGothicURWCon-De... woff2 swap
Size 13 KB
Load time 59 ms
Start 433 ms
Risk FOUT — text flashes from fallback to web font
icomoon.woff woff swap
Size 36 KB
Load time 51 ms
Start 433 ms
Risk FOUT — text flashes from fallback to web font
  • Convert to woff2 for ~30% smaller file size
FranklinGothicURW-Dem.w... woff2 swap
Size 14 KB
Load time 51 ms
Start 434 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 ~11 KB and ~22 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=86400 (1 day)
PASS
max-age=86400 (1 day)
Info::
Cache-Control header is set
Got: public, max-age=86400
Info::
Effective TTL: 1 day (max-age=86400)
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

public, max-age=86400

DirectiveValueMeaning
public—Any cache may store this response
max-age86400Cache for 1 day
Effective TTL: 86400 seconds
Network Waterfall
41 requests over 2363ms
INFO
0 ms 2.0 s 4.0 s 6.0 s 8.0 s 10.0 s 12.0 s 14.0 s 16.0 s 18.0 s 20.0 s 22.0 s 24.0 s 26.0 s 28.0 s FCP 2.6 s LCP 27.7 shttps://iop.org// https://iop.org/ — 301 — 340 B — 8 ms — h2https://www.iop.org/www.iop.org/ https://www.iop.org/ — 200 — 19.9 KiB — 273 ms — h2https://www.iop.org/sites/default/files/css/css_rAtmwcV-HJ3j1zmnwT5PIy0mraVMHE0LdfJhoHdxyPY.css?delta=0&language=en&theme=iop_theme&include=eJxVTlsOwiAQvBCWIzWLjBSzsGQXtO3pbWwa4888M8kE9A6dsTYxxPmR-bDmEyqU2AWmffOBDO7OZPavC8wowS5fJR6dKHzU0YgnetJ6BlW0EOcdLkub-4ICn1gC8W1k10gpKbXFruUvmUZtI3C2BdFZ19zgT3K2WUc5L70y3ua_OBWJg_EBnhVVOQwww.iop.org/sites/default/files/css... https://www.iop.org/sites/default/files/css/css_rAtmwcV-HJ3j1zmnwT5PIy0mraVMHE0LdfJhoHdxyPY.css?delta=0&language=en&theme=iop_theme&include=eJxVTlsOwiAQvBCWIzWLjBSzsGQXtO3pbWwa4888M8kE9A6dsTYxxPmR-bDmEyqU2AWmffOBDO7OZPavC8wowS5fJR6dKHzU0YgnetJ6BlW0EOcdLkub-4ICn1gC8W1k10gpKbXFruUvmUZtI3C2BdFZ19zgT3K2WUc5L70y3ua_OBWJg_EBnhVVOQ — 200 — 2.7 KiB — 32 ms — h2https://www.iop.org/sites/default/files/css/css_YKV4yw1vo42EOKrY3h8MkpEYYrV0o7q0-or32UI8Tk0.css?delta=1&language=en&theme=iop_theme&include=eJxVTlsOwiAQvBCWIzWLjBSzsGQXtO3pbWwa4888M8kE9A6dsTYxxPmR-bDmEyqU2AWmffOBDO7OZPavC8wowS5fJR6dKHzU0YgnetJ6BlW0EOcdLkub-4ICn1gC8W1k10gpKbXFruUvmUZtI3C2BdFZ19zgT3K2WUc5L70y3ua_OBWJg_EBnhVVOQwww.iop.org/sites/default/files/css... https://www.iop.org/sites/default/files/css/css_YKV4yw1vo42EOKrY3h8MkpEYYrV0o7q0-or32UI8Tk0.css?delta=1&language=en&theme=iop_theme&include=eJxVTlsOwiAQvBCWIzWLjBSzsGQXtO3pbWwa4888M8kE9A6dsTYxxPmR-bDmEyqU2AWmffOBDO7OZPavC8wowS5fJR6dKHzU0YgnetJ6BlW0EOcdLkub-4ICn1gC8W1k10gpKbXFruUvmUZtI3C2BdFZ19zgT3K2WUc5L70y3ua_OBWJg_EBnhVVOQ — 200 — 63.9 KiB — 63 ms — h2https://www.iop.org/sites/default/files/js/js_b6LZj6c1gz5idt2o-8QkVwsK-lkMhFq2B74gzi7XeTc.js?scope=header&delta=0&language=en&theme=iop_theme&include=eJxtjEsOwzAIRC_kliMh3EwdV8RENs2np2_k7KJsHrwBTYQ7KmObrWHgd9ZDGyUUVNEQ788NipezqHKxghBVfjvFbE_5yBaSWVKwS6J04Oo3T1PINvMgLio7KmFB8Z75iAmU1KLo45tD85pn0DnCkrE26jxb-8pttJUnq6CL_wEIVF3Vwww.iop.org/sites/default/files/js/... https://www.iop.org/sites/default/files/js/js_b6LZj6c1gz5idt2o-8QkVwsK-lkMhFq2B74gzi7XeTc.js?scope=header&delta=0&language=en&theme=iop_theme&include=eJxtjEsOwzAIRC_kliMh3EwdV8RENs2np2_k7KJsHrwBTYQ7KmObrWHgd9ZDGyUUVNEQ788NipezqHKxghBVfjvFbE_5yBaSWVKwS6J04Oo3T1PINvMgLio7KmFB8Z75iAmU1KLo45tD85pn0DnCkrE26jxb-8pttJUnq6CL_wEIVF3V — 200 — 831 B — 63 ms — h2https://www.iop.org/modules/contrib/google_tag/js/gtag.js?tdi04swww.iop.org/modules/contrib/google_... https://www.iop.org/modules/contrib/google_tag/js/gtag.js?tdi04s — 200 — 1.1 KiB — 63 ms — h2https://www.iop.org/modules/contrib/google_tag/js/gtm.js?tdi04swww.iop.org/modules/contrib/google_... https://www.iop.org/modules/contrib/google_tag/js/gtm.js?tdi04s — 200 — 842 B — 63 ms — h2https://www.iop.org/sites/default/files/styles/component_hero_800_700/public/2019-02/membership-carousel.jpg?itok=NtkJkj_Owww.iop.org/sites/default/files/sty... https://www.iop.org/sites/default/files/styles/component_hero_800_700/public/2019-02/membership-carousel.jpg?itok=NtkJkj_O — 200 — 86.3 KiB — 68 ms — h2https://www.iop.org/sites/default/files/js/js_Ki6p2MbdPgNqjhHP0F6p7XrB0gv4Lc_5vPSzXWBUDfE.js?scope=footer&delta=0&language=en&theme=iop_theme&include=eJxtjEsOwzAIRC_kliMh3EwdV8RENs2np2_k7KJsHrwBTYQ7KmObrWHgd9ZDGyUUVNEQ788NipezqHKxghBVfjvFbE_5yBaSWVKwS6J04Oo3T1PINvMgLio7KmFB8Z75iAmU1KLo45tD85pn0DnCkrE26jxb-8pttJUnq6CL_wEIVF3Vwww.iop.org/sites/default/files/js/... https://www.iop.org/sites/default/files/js/js_Ki6p2MbdPgNqjhHP0F6p7XrB0gv4Lc_5vPSzXWBUDfE.js?scope=footer&delta=0&language=en&theme=iop_theme&include=eJxtjEsOwzAIRC_kliMh3EwdV8RENs2np2_k7KJsHrwBTYQ7KmObrWHgd9ZDGyUUVNEQ788NipezqHKxghBVfjvFbE_5yBaSWVKwS6J04Oo3T1PINvMgLio7KmFB8Z75iAmU1KLo45tD85pn0DnCkrE26jxb-8pttJUnq6CL_wEIVF3V — 200 — 211.3 KiB — 71 ms — h2https://js.stripe.com/v3/js.stripe.com/v3/ https://js.stripe.com/v3/ — 200 — 220.2 KiB — 76 ms — h2https://www.iop.org/sites/default/files/js/js_EB8HHnoaRzJDiYTotyhw_tMrAF480yAEVjnosKdN8fE.js?scope=footer&delta=2&language=en&theme=iop_theme&include=eJxtjEsOwzAIRC_kliMh3EwdV8RENs2np2_k7KJsHrwBTYQ7KmObrWHgd9ZDGyUUVNEQ788NipezqHKxghBVfjvFbE_5yBaSWVKwS6J04Oo3T1PINvMgLio7KmFB8Z75iAmU1KLo45tD85pn0DnCkrE26jxb-8pttJUnq6CL_wEIVF3Vwww.iop.org/sites/default/files/js/... https://www.iop.org/sites/default/files/js/js_EB8HHnoaRzJDiYTotyhw_tMrAF480yAEVjnosKdN8fE.js?scope=footer&delta=2&language=en&theme=iop_theme&include=eJxtjEsOwzAIRC_kliMh3EwdV8RENs2np2_k7KJsHrwBTYQ7KmObrWHgd9ZDGyUUVNEQ788NipezqHKxghBVfjvFbE_5yBaSWVKwS6J04Oo3T1PINvMgLio7KmFB8Z75iAmU1KLo45tD85pn0DnCkrE26jxb-8pttJUnq6CL_wEIVF3V — 200 — 12.9 KiB — 31 ms — h2https://www.googletagmanager.com/gtm.js?id=GTM-53NVWC3www.googletagmanager.com/gtm.js?id=... https://www.googletagmanager.com/gtm.js?id=GTM-53NVWC3 — 200 — 160.6 KiB — 187 ms — h2https://www.iop.org/themes/custom/iop_theme/build/images/logos/iop-logo.svgwww.iop.org/themes/custom/iop_theme... https://www.iop.org/themes/custom/iop_theme/build/images/logos/iop-logo.svg — 200 — 2.5 KiB — 29 ms — h2https://www.iop.org/sites/default/files/2022-09/family-day-001.jpgwww.iop.org/sites/default/files/202... https://www.iop.org/sites/default/files/2022-09/family-day-001.jpg — 200 — 590.0 KiB — 57 ms — 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Other
Costly
Execution 425ms
Transfer 211 KB
Unused 59%
Monthly Cost €5/mo
Unattributable
Other
Costly
Execution 392ms
Transfer 0 KB
Monthly Cost €4/mo
Stripe
Payment
Essential
Execution 240ms
Transfer 220 KB
Unused 73%
Monthly Cost €3/mo
Google Tag Manager
Tag Manager
Costly
Execution 221ms
Transfer 161 KB
Unused 43%
Monthly Cost €2/mo
www.iop.org
Other
Costly
Execution 207ms
Transfer 0 KB
Monthly Cost €2/mo

These scripts may cost more than they're worth

  • www.iop.org adds 468ms and costs ~€5/month
  • www.iop.org adds 425ms and costs ~€5/month
  • Unattributable adds 392ms and costs ~€4/month
  • Google Tag Manager adds 221ms and costs ~€2/month
  • www.iop.org adds 207ms and costs ~€2/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.iop.org takes 468ms 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.iop.org takes 425ms 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 www.iop.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

Unattributable 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

73% of Stripe'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 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

www.iop.org takes 207ms 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

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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