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Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
73
GRADE
C
FIX
5
REVIEW
2
PASS
8
INFO
2

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

Mobile Desktop
41
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
100
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
73
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
91
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.

5.22 s

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

11.89 s

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

892 ms

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

0.002

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

5.22 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.

11.90 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 2 REVIEW 5 FIX
D
Third-Party Impact
Action
94% third-party, 0 ms blocking
FIX
94% third-party, 0 ms blocking
Warning::
Third-party code accounts for 94% of page weight (1.9 MiB of 2.1 MiB)
Info::
Third-party blocking time is low (0 ms)
94%
First-party Third-party
D
JS Execution Cost
Action
3013ms total JS execution
FIX
3013ms total JS execution
Warning::
https://cmp.inmobi.com/tcfv2/61/cmp2ui-en.js: 477ms CPU time
Warning::
https://cmp.inmobi.com/tcfv2/cmp2.js?referer=calib...: 472ms CPU time
Warning::
Unattributable: 443ms CPU time
Warning::
https://www.paypalobjects.com/api/checkout.min.js: 325ms CPU time
Warning::
https://calibre-ebook.com/: 296ms CPU time
Warning::
Third-party scripts: 2561ms (85% of total)

Main Thread Breakdown

Script Evaluation 58% Other 18% Script Parsing & Compilation 14% Style & Layout 6%
ScriptTotalScriptingParse/CompileParty
https://cmp.inmobi.com/tcfv2/61/cmp2ui-en.js477ms302ms50ms3rd
https://cmp.inmobi.com/tcfv2/cmp2.js?referer=calibre-ebook.com472ms303ms52ms3rd
Unattributable443ms60ms0ms3rd
https://www.paypalobjects.com/api/checkout.min.js325ms212ms68ms3rd
https://calibre-ebook.com/296ms194ms6ms1st
https://www.googletagmanager.com/gtag/js?id=G-YMW4X5CSKP219ms154ms64ms3rd
https://a.pub.network/calibre-ebook-com/prebid.js209ms140ms69ms3rd
https://calibre-ebook.com/resources/js/jquery.tools.min.js157ms71ms9ms1st
https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604160201/pubads_impl.js147ms97ms47ms3rd
https://a.pub.network/calibre-ebook-com/pubfig.engine.mobile.js130ms90ms40ms3rd

Showing top 10 of 12 scripts

F
JS Bundles
Action
14 scripts, 734 KB unused
FIX
14 scripts, 734 KB unused
Warning::
https://a.pub.network/calibre-ebook-com/prebid.js: 150 KB unused (82%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://securepubads.g.doubleclick.net/pagead/mana...: 145 KB unused (77%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://a.pub.network/calibre-ebook-com/pubfig.eng...: 111 KB unused (79%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.googletagmanager.com/gtag/js?id=G-YMW4...: 77 KB unused (50%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://cmp.inmobi.com/tcfv2/61/cmp2ui-en.js: 59 KB unused (47%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 734 KB
734 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://a.pub.network/calibre-ebook-com/prebid.js184 KB150 KB (82%)✓3rd
https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604160201/pubads_impl.js188 KB145 KB (77%)✓3rd
https://a.pub.network/calibre-ebook-com/pubfig.engine.mobile.js140 KB111 KB (79%)✓3rd
https://www.googletagmanager.com/gtag/js?id=G-YMW4X5CSKP154 KB77 KB (50%)✓3rd
https://cmp.inmobi.com/tcfv2/61/cmp2ui-en.js125 KB59 KB (47%)✓3rd
https://cmp.inmobi.com/tcfv2/cmp2.js?referer=calibre-ebook.com116 KB58 KB (50%)✓3rd
https://www.paypalobjects.com/api/checkout.min.js169 KB56 KB (34%)✓3rd
https://www.paypalobjects.com/api/checkout.min.js169 KB56 KB (34%)✓3rd
https://calibre-ebook.com/resources/js/jquery.tools.min.js35 KB21 KB (61%)✓1st
https://www.paypal.com/tagmanager/pptm.js?id=calibre-ebook.com&source=checkoutjs&t=xo&v=4.0.3472 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

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

F
Page Weight Inventory
Action
56 resources · 2.1 MB · 734 KB savings available
FIX
56 resources · 2.1 MB · 734 KB savings available
Warning::
Page weight 1.1 MB over 1MB target
Got: 2.1 MB Expected: ≤ 1 MB
Info::
~734 KB of savings available
Warning::
41 third-party resources (94% of weight)
Info::
1 resources over 200KB
56 resources · 2.1 MiB · 41 third-party 1.1 MiB over 1MB target
JavaScript 67% · 1.4 MiB
Media 19% · 400.6 KiB
Other 8% · 170.6 KiB
Image 4% · 89.9 KiB
Document 1% · 22.3 KiB
CSS 0% · 2.9 KiB

~734.0 KiB of savings available

Remove unused JavaScript: 734.0 KiB
D
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.
Info::
ETag present — enables conditional (304) responses
Info::
Last-Modified header present

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

C
Page Weight Budget
Action
2.1 MB transferred, 56 requests
REVIEW
2.1 MB transferred, 56 requests
Info::
Page weighs 8.8 MB (2.1 MB transferred)
Warning::
JavaScript is 1.4 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.4 MB
Info::
56 HTTP requests
Info::
Estimated 0.43 g CO2 per page load
2.1 MB / 2.4 MB budget
2.1 MB transferred
56 requests
0.43 g CO2 per page load
JavaScript 1.4 MiB 67%
Other 400.6 KiB 19%
Other 135.9 KiB 6%
Images 73.2 KiB 3%
Other 48.5 KiB 2%
HTML 22.3 KiB 1%
CSS 2.9 KiB 0%
Other 2.2 KiB 0%
Other 646 B 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Approaching limit

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

C
Image Optimization
Action
10 images, 0 KB saveable
REVIEW
10 images, 0 KB saveable
Warning::
https://calibre-ebook.com/resources/img/home-featu... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://calibre-ebook.com/resources/img/home-tag.p... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
10 images 73 KB
0 oversized -0 KB
9 legacy format
2 missing dimensions CLS 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

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
No web fonts (system fonts)
PASS
No web fonts (system fonts)
Info::
No web fonts loaded — system fonts are fastest
No web fonts loaded — system fonts are optimal.
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+
Green Hosting
Whether the site is served from green-energy infrastructure
PASS

Green Hosting

This site is hosted on green energy infrastructure

Provider: OVHcloud

Network Waterfall
56 requests over 1899ms
INFO
0 ms 2.0 s 4.0 s 6.0 s 8.0 s 10.0 s 12.0 s FCP 5.2 s LCP 11.9 shttps://calibre-ebook.com// https://calibre-ebook.com/ — 200 — 7.7 KiB — 298 ms — h2https://a.pub.network/calibre-ebook-com/cls.cssa.pub.network/calibre-ebook-com/cls... https://a.pub.network/calibre-ebook-com/cls.css — 200 — 616 B — 209 ms — h3https://calibre-ebook.com/resources/js/jquery.tools.min.js/resources/js/jquery.tools.min.js https://calibre-ebook.com/resources/js/jquery.tools.min.js — 200 — 35.3 KiB — 198 ms — h2https://calibre-ebook.com/resources/styles/yui.css/resources/styles/yui.css https://calibre-ebook.com/resources/styles/yui.css — 200 — 862 B — 97 ms — h2https://calibre-ebook.com/resources/styles/base.css/resources/styles/base.css https://calibre-ebook.com/resources/styles/base.css — 200 — 1.4 KiB — 99 ms — h2https://calibre-ebook.com/resources/img/home-feature.jpg/resources/img/home-feature.jpg https://calibre-ebook.com/resources/img/home-feature.jpg — 200 — 23.9 KiB — 196 ms — h2https://calibre-ebook.com/resources/img/home-tag.png/resources/img/home-tag.png https://calibre-ebook.com/resources/img/home-tag.png — 200 — 7.3 KiB — 197 ms — h2https://calibre-ebook.com/resources/img/spinner.gif/resources/img/spinner.gif https://calibre-ebook.com/resources/img/spinner.gif — 200 — 6.8 KiB — 96 ms — h2https://www.googletagmanager.com/gtag/js?id=G-YMW4X5CSKPwww.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=G-YMW4X5CSKP — 200 — 154.3 KiB — 162 ms — h2https://www.paypalobjects.com/api/checkout.min.jswww.paypalobjects.com/api/checkout.... https://www.paypalobjects.com/api/checkout.min.js — 200 — 169.3 KiB — 70 ms — h2https://cmp.inmobi.com/choice/593Yp13RM2k2D/calibre-ebook.com/choice.js?tag_version=V3cmp.inmobi.com/choice/593Yp13RM2k2D... https://cmp.inmobi.com/choice/593Yp13RM2k2D/calibre-ebook.com/choice.js?tag_version=V3 — 200 — 2.0 KiB — 176 ms — h2https://a.pub.network/calibre-ebook-com/pubfig.min.jsa.pub.network/calibre-ebook-com/pub... https://a.pub.network/calibre-ebook-com/pubfig.min.js — 200 — 26.2 KiB — 42 ms — h3https://calibre-ebook.com/country-code/country-code https://calibre-ebook.com/country-code — 200 — 111 B — 96 ms — h2https://download.calibre-ebook.com/videos/grand-tour.mp4download.calibre-ebook.com/videos/g... https://download.calibre-ebook.com/videos/grand-tour.mp4 — 206 — 400.6 KiB — 626 ms — h2https://calibre-ebook.com/resources/img/logo.png/resources/img/logo.png https://calibre-ebook.com/resources/img/logo.png — 200 — 13.2 KiB — 97 ms — h2https://calibre-ebook.com/resources/img/bg.png/resources/img/bg.png https://calibre-ebook.com/resources/img/bg.png — 200 — 553 B — 99 ms — h2https://calibre-ebook.com/resources/img/blank.png/resources/img/blank.png https://calibre-ebook.com/resources/img/blank.png — 200 — 266 B — 100 ms — h2https://calibre-ebook.com/resources/img/button-download.png/resources/img/button-download.png https://calibre-ebook.com/resources/img/button-download.png — 200 — 2.7 KiB — 99 ms — h2https://calibre-ebook.com/resources/img/button-getinvolved.png/resources/img/button-getinvolved.p... https://calibre-ebook.com/resources/img/button-getinvolved.png — 200 — 2.0 KiB — 100 ms — h2https://d.pub.network/v2/sites/calibre-ebook-com/configs?env=PRODd.pub.network/v2/sites/calibre-eboo... https://d.pub.network/v2/sites/calibre-ebook-com/configs?env=PROD — 200 — 8.9 KiB — 117 ms — h2https://www.paypal.com/tagmanager/pptm.js?id=calibre-ebook.com&source=checkoutjs&t=xo&v=4.0.347www.paypal.com/tagmanager/pptm.js?i... https://www.paypal.com/tagmanager/pptm.js?id=calibre-ebook.com&source=checkoutjs&t=xo&v=4.0.347 — 410 — 2.2 KiB — 331 ms — h2data:image/svg+xml;base64,PHN2ZyB3aWR0aD0iMTAwIiBoZWlnaHQ9IjMyIiB2aWV3Qm94PSIwIDAgMTAwIDMyIiB4bWxuc…data:image/svg+xml;base64,PHN2ZyB3a... data:image/svg+xml;base64,PHN2ZyB3aWR0aD0iMTAwIiBoZWlnaHQ9IjMyIiB2aWV3Qm94PSIwIDAgMTAwIDMyIiB4bWxuc… — 200 — 0 B — 0 ms — datahttps://www.paypal.com/xoplatform/logger/api/loggerwww.paypal.com/xoplatform/logger/ap... https://www.paypal.com/xoplatform/logger/api/logger — 204 — 0 B — 223 ms — h2https://www.paypal.com/smart/button?env=production&commit=true&style.tagline=false&style.label=pay&locale.x=en_US&domain=calibre-ebook.com&sessionID=uid_ac46953df6_mjm6mty6ntu&buttonSessionID=uid_e2530b77c9_mjm6mty6ntu&renderedButtons=paypal&storageID=uid_d11e29c342_mjm6mty6ntu&logLevel=warn&sdkMeta=eyJ1cmwiOiJodHRwczovL3d3dy5wYXlwYWxvYmplY3RzLmNvbS9hcGkvY2hlY2tvdXQubWluLmpzIn0&uid=6feb34391e&version=min&xcomponent=1www.paypal.com/smart/button?env=pro... https://www.paypal.com/smart/button?env=production&commit=true&style.tagline=false&style.label=pay&locale.x=en_US&domain=calibre-ebook.com&sessionID=uid_ac46953df6_mjm6mty6ntu&buttonSessionID=uid_e2530b77c9_mjm6mty6ntu&renderedButtons=paypal&storageID=uid_d11e29c342_mjm6mty6ntu&logLevel=warn&sdkMeta=eyJ1cmwiOiJodHRwczovL3d3dy5wYXlwYWxvYmplY3RzLmNvbS9hcGkvY2hlY2tvdXQubWluLmpzIn0&uid=6feb34391e&version=min&xcomponent=1 — 200 — 14.7 KiB — 392 ms — h2https://c.pub.network/v2/cc.pub.network/v2/c https://c.pub.network/v2/c — 200 — 0 B — 110 ms — h2https://a.pub.network/calibre-ebook-com/prebid.jsa.pub.network/calibre-ebook-com/pre... https://a.pub.network/calibre-ebook-com/prebid.js — 200 — 183.7 KiB — 89 ms — h3https://securepubads.g.doubleclick.net/tag/js/gpt.jssecurepubads.g.doubleclick.net/tag/... https://securepubads.g.doubleclick.net/tag/js/gpt.js — 200 — 33.8 KiB — 148 ms — h3https://a.pub.network/calibre-ebook-com/pubfig.engine.mobile.jsa.pub.network/calibre-ebook-com/pub... https://a.pub.network/calibre-ebook-com/pubfig.engine.mobile.js — 200 — 140.2 KiB — 99 ms — h3https://cmp.inmobi.com/tcfv2/cmp2.js?referer=calibre-ebook.comcmp.inmobi.com/tcfv2/cmp2.js?refere... https://cmp.inmobi.com/tcfv2/cmp2.js?referer=calibre-ebook.com — 200 — 116.4 KiB — 52 ms — h2https://c.pub.network/v2/cc.pub.network/v2/c https://c.pub.network/v2/c — 200 — 111 B — 33 ms — h2
0 ms 2.0 s 4.0 s 6.0 s 8.0 s 10.0 s 12.0 s FCP 5.2 s LCP 11.9 shttps://calibre-ebook.com// https://calibre-ebook.com/ — 200 — 7.7 KiB — 298 ms — h2https://a.pub.network/calibre-ebook-com/cls.cssa.pub.network/calibre-ebook-com/cls... https://a.pub.network/calibre-ebook-com/cls.css — 200 — 616 B — 209 ms — h3https://calibre-ebook.com/resources/js/jquery.tools.min.js/resources/js/jquery.tools.min.js https://calibre-ebook.com/resources/js/jquery.tools.min.js — 200 — 35.3 KiB — 198 ms — h2https://calibre-ebook.com/resources/styles/yui.css/resources/styles/yui.css https://calibre-ebook.com/resources/styles/yui.css — 200 — 862 B — 97 ms — h2https://calibre-ebook.com/resources/styles/base.css/resources/styles/base.css https://calibre-ebook.com/resources/styles/base.css — 200 — 1.4 KiB — 99 ms — h2https://calibre-ebook.com/resources/img/home-feature.jpg/resources/img/home-feature.jpg https://calibre-ebook.com/resources/img/home-feature.jpg — 200 — 23.9 KiB — 196 ms — h2https://calibre-ebook.com/resources/img/home-tag.png/resources/img/home-tag.png https://calibre-ebook.com/resources/img/home-tag.png — 200 — 7.3 KiB — 197 ms — h2https://calibre-ebook.com/resources/img/spinner.gif/resources/img/spinner.gif https://calibre-ebook.com/resources/img/spinner.gif — 200 — 6.8 KiB — 96 ms — h2https://www.googletagmanager.com/gtag/js?id=G-YMW4X5CSKPwww.googletagmanager.com/gtag/js?id... https://www.googletagmanager.com/gtag/js?id=G-YMW4X5CSKP — 200 — 154.3 KiB — 162 ms — h2https://www.paypalobjects.com/api/checkout.min.jswww.paypalobjects.com/api/checkout.... https://www.paypalobjects.com/api/checkout.min.js — 200 — 169.3 KiB — 70 ms — h2https://cmp.inmobi.com/choice/593Yp13RM2k2D/calibre-ebook.com/choice.js?tag_version=V3cmp.inmobi.com/choice/593Yp13RM2k2D... https://cmp.inmobi.com/choice/593Yp13RM2k2D/calibre-ebook.com/choice.js?tag_version=V3 — 200 — 2.0 KiB — 176 ms — h2https://a.pub.network/calibre-ebook-com/pubfig.min.jsa.pub.network/calibre-ebook-com/pub... https://a.pub.network/calibre-ebook-com/pubfig.min.js — 200 — 26.2 KiB — 42 ms — h3https://calibre-ebook.com/country-code/country-code https://calibre-ebook.com/country-code — 200 — 111 B — 96 ms — h2https://download.calibre-ebook.com/videos/grand-tour.mp4download.calibre-ebook.com/videos/g... https://download.calibre-ebook.com/videos/grand-tour.mp4 — 206 — 400.6 KiB — 626 ms — h2https://calibre-ebook.com/resources/img/logo.png/resources/img/logo.png https://calibre-ebook.com/resources/img/logo.png — 200 — 13.2 KiB — 97 ms — h2https://calibre-ebook.com/resources/img/bg.png/resources/img/bg.png https://calibre-ebook.com/resources/img/bg.png — 200 — 553 B — 99 ms — h2https://calibre-ebook.com/resources/img/blank.png/resources/img/blank.png https://calibre-ebook.com/resources/img/blank.png — 200 — 266 B — 100 ms — h2https://calibre-ebook.com/resources/img/button-download.png/resources/img/button-download.png https://calibre-ebook.com/resources/img/button-download.png — 200 — 2.7 KiB — 99 ms — h2https://calibre-ebook.com/resources/img/button-getinvolved.png/resources/img/button-getinvolved.p... https://calibre-ebook.com/resources/img/button-getinvolved.png — 200 — 2.0 KiB — 100 ms — h2https://d.pub.network/v2/sites/calibre-ebook-com/configs?env=PRODd.pub.network/v2/sites/calibre-eboo... https://d.pub.network/v2/sites/calibre-ebook-com/configs?env=PROD — 200 — 8.9 KiB — 117 ms — h2https://www.paypal.com/tagmanager/pptm.js?id=calibre-ebook.com&source=checkoutjs&t=xo&v=4.0.347www.paypal.com/tagmanager/pptm.js?i... https://www.paypal.com/tagmanager/pptm.js?id=calibre-ebook.com&source=checkoutjs&t=xo&v=4.0.347 — 410 — 2.2 KiB — 331 ms — h2data:image/svg+xml;base64,PHN2ZyB3aWR0aD0iMTAwIiBoZWlnaHQ9IjMyIiB2aWV3Qm94PSIwIDAgMTAwIDMyIiB4bWxuc…data:image/svg+xml;base64,PHN2ZyB3a... data:image/svg+xml;base64,PHN2ZyB3aWR0aD0iMTAwIiBoZWlnaHQ9IjMyIiB2aWV3Qm94PSIwIDAgMTAwIDMyIiB4bWxuc… — 200 — 0 B — 0 ms — datahttps://www.paypal.com/xoplatform/logger/api/loggerwww.paypal.com/xoplatform/logger/ap... https://www.paypal.com/xoplatform/logger/api/logger — 204 — 0 B — 223 ms — h2https://www.paypal.com/smart/button?env=production&commit=true&style.tagline=false&style.label=pay&locale.x=en_US&domain=calibre-ebook.com&sessionID=uid_ac46953df6_mjm6mty6ntu&buttonSessionID=uid_e2530b77c9_mjm6mty6ntu&renderedButtons=paypal&storageID=uid_d11e29c342_mjm6mty6ntu&logLevel=warn&sdkMeta=eyJ1cmwiOiJodHRwczovL3d3dy5wYXlwYWxvYmplY3RzLmNvbS9hcGkvY2hlY2tvdXQubWluLmpzIn0&uid=6feb34391e&version=min&xcomponent=1www.paypal.com/smart/button?env=pro... https://www.paypal.com/smart/button?env=production&commit=true&style.tagline=false&style.label=pay&locale.x=en_US&domain=calibre-ebook.com&sessionID=uid_ac46953df6_mjm6mty6ntu&buttonSessionID=uid_e2530b77c9_mjm6mty6ntu&renderedButtons=paypal&storageID=uid_d11e29c342_mjm6mty6ntu&logLevel=warn&sdkMeta=eyJ1cmwiOiJodHRwczovL3d3dy5wYXlwYWxvYmplY3RzLmNvbS9hcGkvY2hlY2tvdXQubWluLmpzIn0&uid=6feb34391e&version=min&xcomponent=1 — 200 — 14.7 KiB — 392 ms — h2https://c.pub.network/v2/cc.pub.network/v2/c https://c.pub.network/v2/c — 200 — 0 B — 110 ms — h2https://a.pub.network/calibre-ebook-com/prebid.jsa.pub.network/calibre-ebook-com/pre... https://a.pub.network/calibre-ebook-com/prebid.js — 200 — 183.7 KiB — 89 ms — h3https://securepubads.g.doubleclick.net/tag/js/gpt.jssecurepubads.g.doubleclick.net/tag/... https://securepubads.g.doubleclick.net/tag/js/gpt.js — 200 — 33.8 KiB — 148 ms — h3https://a.pub.network/calibre-ebook-com/pubfig.engine.mobile.jsa.pub.network/calibre-ebook-com/pub... https://a.pub.network/calibre-ebook-com/pubfig.engine.mobile.js — 200 — 140.2 KiB — 99 ms — h3https://cmp.inmobi.com/tcfv2/cmp2.js?referer=calibre-ebook.comcmp.inmobi.com/tcfv2/cmp2.js?refere... https://cmp.inmobi.com/tcfv2/cmp2.js?referer=calibre-ebook.com — 200 — 116.4 KiB — 52 ms — h2https://c.pub.network/v2/cc.pub.network/v2/c https://c.pub.network/v2/c — 200 — 111 B — 33 ms — h2https://www.paypal.com/xoplatform/logger/api/loggerwww.paypal.com/xoplatform/logger/ap... https://www.paypal.com/xoplatform/logger/api/logger — 200 — 1.7 KiB — 270 ms — h2https://cmp.inmobi.com/geoipcmp.inmobi.com/geoip https://cmp.inmobi.com/geoip — 200 — 331 B — 54 ms — h2https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604160201/pubads_impl.jssecurepubads.g.doubleclick.net/page... https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604160201/pubads_impl.js — 200 — 187.7 KiB — 84 ms — h3https://cmp.inmobi.com/GVL-v3/vendor-list-trimmed-v1.jsoncmp.inmobi.com/GVL-v3/vendor-list-t... https://cmp.inmobi.com/GVL-v3/vendor-list-trimmed-v1.json — 200 — 75.9 KiB — 44 ms — h2https://cmp.inmobi.com/GVL-v2/cmp-list.jsoncmp.inmobi.com/GVL-v2/cmp-list.json https://cmp.inmobi.com/GVL-v2/cmp-list.json — 200 — 5.1 KiB — 19 ms — h2https://cmp.inmobi.com/tcfv2/61/cmp2ui-en.jscmp.inmobi.com/tcfv2/61/cmp2ui-en.j... https://cmp.inmobi.com/tcfv2/61/cmp2ui-en.js — 200 — 125.3 KiB — 26 ms — h2https://www.paypalobjects.com/api/checkout.min.jswww.paypalobjects.com/api/checkout.... https://www.paypalobjects.com/api/checkout.min.js — 200 — 169.3 KiB — 167 ms — h3https://www.paypalobjects.com/api/xo/button.js?date=2026-3-22www.paypalobjects.com/api/xo/button... https://www.paypalobjects.com/api/xo/button.js?date=2026-3-22 — 200 — 67.5 KiB — 170 ms — h3https://visit-server.inmobi-choice.io/visit-eventvisit-server.inmobi-choice.io/visit... https://visit-server.inmobi-choice.io/visit-event — 200 — 0 B — 120 ms — h2https://cmp.inmobi.com/us-mspa/v1/purposes-national-en.jsoncmp.inmobi.com/us-mspa/v1/purposes-... https://cmp.inmobi.com/us-mspa/v1/purposes-national-en.json — 200 — 1.8 KiB — 18 ms — h2data:image/svg+xml;base64,PHN2ZyB3aWR0aD0iMTAwIiBoZWlnaHQ9IjMyIiB2aWV3Qm94PSIwIDAgMTAwIDMyIiB4bWxuc…data:image/svg+xml;base64,PHN2ZyB3a... data:image/svg+xml;base64,PHN2ZyB3aWR0aD0iMTAwIiBoZWlnaHQ9IjMyIiB2aWV3Qm94PSIwIDAgMTAwIDMyIiB4bWxuc… — 200 — 0 B — 0 ms — datahttps://cmp.inmobi.com/GVL-v3/vendor-list-trimmed-v1.jsoncmp.inmobi.com/GVL-v3/vendor-list-t... https://cmp.inmobi.com/GVL-v3/vendor-list-trimmed-v1.json — 200 — 0 B — 4 ms — h2https://cmp.inmobi.com/tcfv2/google-atp-list.jsoncmp.inmobi.com/tcfv2/google-atp-lis... https://cmp.inmobi.com/tcfv2/google-atp-list.json — 200 — 38.9 KiB — 25 ms — h2https://cmp.inmobi.com/google-basic-consent/v1/purposes-en.jsoncmp.inmobi.com/google-basic-consent... https://cmp.inmobi.com/google-basic-consent/v1/purposes-en.json — 200 — 1.1 KiB — 24 ms — h2https://api.cmp.inmobi.com/?log=%7B%22accountId%22%3A%22593Yp13RM2k2D%22%2C%22domain%22%3A%22calibre-ebook.com%22%2C%22publisher%22%3A%22calibre%22%2C%22cmpId%22%3A10%2C%22cmpVersion%22%3A%222.61%22%2C%22displayType%22%3A%22tcfui%3Amandatory%22%2C%22configurationHashCode%22%3A%2257MYweZLtzfnUjfkXxTwLg%22%2C%22tagVersion%22%3A%22V3%22%2C%22gvlVersion%22%3A3%2C%22siteUuid%22%3A%227d35c9f0-c604-4124-a470-c1a4447268e6%22%2C%22browserName%22%3A%22Chrome%22%2C%22deviceType%22%3A%22mobile%22%2C%22cmpPlatform%22%3A%22others%22%2C%22pageFormat%22%3A%22HTTP%22%2C%22country%22%3A%22esp%22%2C%22region%22%3A%22md%22%2C%22city%22%3A%22madrid%22%2C%22configs%22%3A%7B%22gbcApplicable%22%3Atrue%2C%22themeUuid%22%3A%227ef284a7-95ee-46c5-ab1d-53a80b077e2c%22%2C%22language%22%3A%22en%22%2C%22copApplicable%22%3Afalse%2C%22advancedApplicable%22%3Afalse%7D%2C%22existingCMPStatus%22%3Anull%2C%22existingGBCStatus%22%3Anull%2C%22existingConfigs%22%3A%7B%7D%2C%22manualTrigger%22%3Afalse%2C%22clientTimestamp%22%3A1776899816199%2C%22operationType%22%3A%22init%22%2C%22sessionId%22%3A%22GDPR-k5bxg7pbr4ia92by8bgv%22%7Dapi.cmp.inmobi.com/?log=%7B%22accou... https://api.cmp.inmobi.com/?log=%7B%22accountId%22%3A%22593Yp13RM2k2D%22%2C%22domain%22%3A%22calibre-ebook.com%22%2C%22publisher%22%3A%22calibre%22%2C%22cmpId%22%3A10%2C%22cmpVersion%22%3A%222.61%22%2C%22displayType%22%3A%22tcfui%3Amandatory%22%2C%22configurationHashCode%22%3A%2257MYweZLtzfnUjfkXxTwLg%22%2C%22tagVersion%22%3A%22V3%22%2C%22gvlVersion%22%3A3%2C%22siteUuid%22%3A%227d35c9f0-c604-4124-a470-c1a4447268e6%22%2C%22browserName%22%3A%22Chrome%22%2C%22deviceType%22%3A%22mobile%22%2C%22cmpPlatform%22%3A%22others%22%2C%22pageFormat%22%3A%22HTTP%22%2C%22country%22%3A%22esp%22%2C%22region%22%3A%22md%22%2C%22city%22%3A%22madrid%22%2C%22configs%22%3A%7B%22gbcApplicable%22%3Atrue%2C%22themeUuid%22%3A%227ef284a7-95ee-46c5-ab1d-53a80b077e2c%22%2C%22language%22%3A%22en%22%2C%22copApplicable%22%3Afalse%2C%22advancedApplicable%22%3Afalse%7D%2C%22existingCMPStatus%22%3Anull%2C%22existingGBCStatus%22%3Anull%2C%22existingConfigs%22%3A%7B%7D%2C%22manualTrigger%22%3Afalse%2C%22clientTimestamp%22%3A1776899816199%2C%22operationType%22%3A%22init%22%2C%22sessionId%22%3A%22GDPR-k5bxg7pbr4ia92by8bgv%22%7D — 200 — 101 B — 182 ms — h2https://cmp.inmobi.com/geoipcmp.inmobi.com/geoip https://cmp.inmobi.com/geoip — 200 — 329 B — 23 ms — h2https://cmp.inmobi.com/custom-translations/inmobi/7ef284a7-95ee-46c5-ab1d-53a80b077e2c/en.jsoncmp.inmobi.com/custom-translations/... https://cmp.inmobi.com/custom-translations/inmobi/7ef284a7-95ee-46c5-ab1d-53a80b077e2c/en.json — 200 — 535 B — 181 ms — h2https://calibre-ebook.com/favicon.png?qc-size=256,256/favicon.png?qc-size=256,256 https://calibre-ebook.com/favicon.png?qc-size=256,256 — 200 — 16.6 KiB — 97 ms — h2https://www.paypal.com/v1/oauth2/tokenwww.paypal.com/v1/oauth2/token https://www.paypal.com/v1/oauth2/token — 200 — 1.2 KiB — 244 ms — h2https://www.paypal.com/smart/api/button/funding?buttonLabel=pay&buttonSessionID=uid_e2530b77c9_mjm6mty6ntu&country=US&domain=calibre-ebook.com&lang=en&renderedButtons=paypalwww.paypal.com/smart/api/button/fun... https://www.paypal.com/smart/api/button/funding?buttonLabel=pay&buttonSessionID=uid_e2530b77c9_mjm6mty6ntu&country=US&domain=calibre-ebook.com&lang=en&renderedButtons=paypal — 200 — 3.0 KiB — 348 ms — h2https://www.paypal.com/xoplatform/logger/api/loggerwww.paypal.com/xoplatform/logger/ap... https://www.paypal.com/xoplatform/logger/api/logger — 200 — 1.4 KiB — 247 ms — h2https://www.paypal.com/xoplatform/logger/api/loggerwww.paypal.com/xoplatform/logger/ap... https://www.paypal.com/xoplatform/logger/api/logger — 200 — 2.3 KiB — 233 ms — h2https://calibre-ebook.com/favicon.png/favicon.png https://calibre-ebook.com/favicon.png — 200 — 16.6 KiB — 97 ms — h2https://securepubads.g.doubleclick.net/pagead/managed/dict/m202604210101/gptsecurepubads.g.doubleclick.net/page... https://securepubads.g.doubleclick.net/pagead/managed/dict/m202604210101/gpt — 200 — 23.0 KiB — 41 ms — h3https://www.paypal.com/graphql?GetNativeEligibilitywww.paypal.com/graphql?GetNativeEli... https://www.paypal.com/graphql?GetNativeEligibility — 200 — 2.6 KiB — 277 ms — h2https://www.paypal.com/xoplatform/logger/api/loggerwww.paypal.com/xoplatform/logger/ap... https://www.paypal.com/xoplatform/logger/api/logger — 200 — 2.2 KiB — 236 ms — h2
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
85% of JavaScript execution is third-party
First-party Third-party 2561ms · 1137KB · €28/mo
cmp.inmobi.com
Other
Costly
Execution 477ms
Transfer 125 KB
Unused 47%
Monthly Cost €5/mo
cmp.inmobi.com
Other
Costly
Execution 472ms
Transfer 116 KB
Unused 50%
Monthly Cost €5/mo
Unattributable
Other
Costly
Execution 443ms
Transfer 0 KB
Monthly Cost €5/mo
www.paypalobjects.com
Other
Costly
Execution 325ms
Transfer 169 KB
Unused 34%
Monthly Cost €4/mo
Google Tag Manager
Tag Manager
Costly
Execution 219ms
Transfer 154 KB
Unused 50%
Monthly Cost €2/mo
a.pub.network
Other
Costly
Execution 209ms
Transfer 184 KB
Unused 82%
Monthly Cost €2/mo
securepubads.g.doubleclick.net
Other
Optional
Execution 147ms
Transfer 188 KB
Unused 77%
Monthly Cost €2/mo
a.pub.network
Other
Optional
Execution 130ms
Transfer 140 KB
Unused 79%
Monthly Cost €1/mo
securepubads.g.doubleclick.net
Other
Optional
Execution 73ms
Transfer 34 KB
Monthly Cost €1/mo
a.pub.network
Other
Optional
Execution 66ms
Transfer 26 KB
Monthly Cost €1/mo

These scripts may cost more than they're worth

  • cmp.inmobi.com adds 477ms and costs ~€5/month
  • cmp.inmobi.com adds 472ms and costs ~€5/month
  • Unattributable adds 443ms and costs ~€5/month
  • www.paypalobjects.com adds 325ms and costs ~€4/month
  • Google Tag Manager adds 219ms and costs ~€2/month
  • a.pub.network adds 209ms and costs ~€2/month

85% 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

cmp.inmobi.com takes 477ms 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

cmp.inmobi.com takes 472ms 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 443ms 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.paypalobjects.com takes 325ms 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 219ms 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

50% 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

a.pub.network takes 209ms 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

82% of a.pub.network'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

77% 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

79% of a.pub.network'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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