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https://calibre-ebook.com

Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
73
GRADE
C
FIX
4
REVIEW
3
PASS
6
INFO
2

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

Mobile Desktop
98
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.
77
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.

747 ms

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

747 ms

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

14 ms

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

0.004

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

1.25 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.

2.40 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
15
6 PASS 3 REVIEW 4 FIX
D
Third-Party Impact
Action
92% third-party, 0 ms blocking
FIX
92% third-party, 0 ms blocking
Warning::
Third-party code accounts for 92% of page weight (1.5 MiB of 1.7 MiB)
Info::
Third-party blocking time is low (0 ms)
92%
First-party Third-party
F
JS Bundles
Action
15 scripts, 732 KB unused
FIX
15 scripts, 732 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...: 144 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 (48%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 732 KB
732 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 KB144 KB (77%)✓3rd
https://a.pub.network/calibre-ebook-com/pubfig.engine.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 (48%)✓3rd
https://cmp.inmobi.com/tcfv2/cmp2.js?referer=calibre-ebook.com116 KB57 KB (49%)✓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://cmp.inmobi.com/choice/593Yp13RM2k2D/calibre-ebook.com/choice.js?tag_version=V32 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
57 resources · 1.7 MB · 732 KB savings available
FIX
57 resources · 1.7 MB · 732 KB savings available
Warning::
Page weight 675 KB over 1MB target
Got: 1.7 MB Expected: ≤ 1 MB
Info::
~732 KB of savings available
Warning::
42 third-party resources (92% of weight)
57 resources · 1.7 MiB · 42 third-party 675.1 KiB over 1MB target
JavaScript 83% · 1.4 MiB
Other 10% · 169.5 KiB
Image 5% · 89.9 KiB
Document 1% · 22.3 KiB
CSS 0% · 2.9 KiB
Media 0% · 134 B

~732.2 KiB of savings available

Remove unused JavaScript: 732.2 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
1.7 MB transferred, 57 requests
REVIEW
1.7 MB transferred, 57 requests
Info::
Page weighs 8.6 MB (1.7 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::
57 HTTP requests
Info::
Estimated 0.35 g CO2 per page load
1.7 MB / 2.4 MB budget
1.7 MB transferred
57 requests
0.35 g CO2 per page load
JavaScript 1.4 MiB 83%
Other 134.7 KiB 8%
Images 73.2 KiB 4%
Other 48.5 KiB 3%
HTML 22.3 KiB 1%
CSS 2.9 KiB 0%
Other 2.4 KiB 0%
Other 648 B 0%
Other 134 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

B
JS Execution Cost
688ms total JS execution
REVIEW
688ms total JS execution
Info::
https://cmp.inmobi.com/tcfv2/cmp2.js?referer=calib...: 130ms CPU time
Info::
https://cmp.inmobi.com/tcfv2/61/cmp2ui-en.js: 113ms CPU time
Info::
https://calibre-ebook.com/: 111ms CPU time
Info::
https://www.paypalobjects.com/api/checkout.min.js: 91ms CPU time
Info::
Unattributable: 75ms CPU time
Warning::
Third-party scripts: 577ms (84% of total)

Main Thread Breakdown

Script Evaluation 64% Other 16% Script Parsing & Compilation 13% Style & Layout 4%
ScriptTotalScriptingParse/CompileParty
https://cmp.inmobi.com/tcfv2/cmp2.js?referer=calibre-ebook.com130ms84ms14ms3rd
https://cmp.inmobi.com/tcfv2/61/cmp2ui-en.js113ms85ms10ms3rd
https://calibre-ebook.com/111ms59ms1ms1st
https://www.paypalobjects.com/api/checkout.min.js91ms61ms21ms3rd
Unattributable75ms11ms0ms3rd
https://www.googletagmanager.com/gtag/js?id=G-YMW4X5CSKP62ms47ms15ms3rd
https://securepubads.g.doubleclick.net/pagead/managed/js/gpt/m202604160201/pubads_impl.js56ms42ms13ms3rd
https://a.pub.network/calibre-ebook-com/prebid.js50ms37ms13ms3rd
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+
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
57 requests over 1960ms
INFO
0 ms 500 ms 1.0 s 1.5 s 2.0 s FCP 747 ms LCP 747 mshttps://calibre-ebook.com// https://calibre-ebook.com/ — 200 — 7.7 KiB — 291 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 — 612 B — 49 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 — 191 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 — 98 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 — 193 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 — 194 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 — 171 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 — 164 ms — h3https://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 — 56 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 — 44 ms — h3https://calibre-ebook.com/country-code/country-code https://calibre-ebook.com/country-code — 200 — 111 B — 95 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 — 96 ms — h2https://calibre-ebook.com/resources/img/bg.png/resources/img/bg.png https://calibre-ebook.com/resources/img/bg.png — 200 — 553 B — 97 ms — h2https://calibre-ebook.com/resources/img/blank.png/resources/img/blank.png https://calibre-ebook.com/resources/img/blank.png — 200 — 266 B — 98 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 — 97 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 — 98 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 — 134 B — 603 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 — 80 ms — h2https://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 — 57 ms — h2https://cmp.inmobi.com/geoipcmp.inmobi.com/geoip https://cmp.inmobi.com/geoip — 200 — 331 B — 52 ms — h2https://c.pub.network/v2/cc.pub.network/v2/c https://c.pub.network/v2/c — 200 — 0 B — 74 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 — 93 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 — 132 ms — h3https://a.pub.network/calibre-ebook-com/pubfig.engine.jsa.pub.network/calibre-ebook-com/pub... https://a.pub.network/calibre-ebook-com/pubfig.engine.js — 200 — 140.2 KiB — 135 ms — h3https://www.paypal.com/tagmanager/pptm.js?id=calibre-ebook.com&source=checkoutjs&t=xo&v=4.0.344www.paypal.com/tagmanager/pptm.js?i... https://www.paypal.com/tagmanager/pptm.js?id=calibre-ebook.com&source=checkoutjs&t=xo&v=4.0.344 — 200 — 1.7 KiB — 38 ms — h2https://c.pub.network/v2/cc.pub.network/v2/c https://c.pub.network/v2/c — 200 — 111 B — 46 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 — 75.9 KiB — 64 ms — h2
0 ms 500 ms 1.0 s 1.5 s 2.0 s FCP 747 ms LCP 747 mshttps://calibre-ebook.com// https://calibre-ebook.com/ — 200 — 7.7 KiB — 291 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 — 612 B — 49 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 — 191 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 — 98 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 — 193 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 — 194 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 — 171 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 — 164 ms — h3https://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 — 56 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 — 44 ms — h3https://calibre-ebook.com/country-code/country-code https://calibre-ebook.com/country-code — 200 — 111 B — 95 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 — 96 ms — h2https://calibre-ebook.com/resources/img/bg.png/resources/img/bg.png https://calibre-ebook.com/resources/img/bg.png — 200 — 553 B — 97 ms — h2https://calibre-ebook.com/resources/img/blank.png/resources/img/blank.png https://calibre-ebook.com/resources/img/blank.png — 200 — 266 B — 98 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 — 97 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 — 98 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 — 134 B — 603 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 — 80 ms — h2https://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 — 57 ms — h2https://cmp.inmobi.com/geoipcmp.inmobi.com/geoip https://cmp.inmobi.com/geoip — 200 — 331 B — 52 ms — h2https://c.pub.network/v2/cc.pub.network/v2/c https://c.pub.network/v2/c — 200 — 0 B — 74 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 — 93 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 — 132 ms — h3https://a.pub.network/calibre-ebook-com/pubfig.engine.jsa.pub.network/calibre-ebook-com/pub... https://a.pub.network/calibre-ebook-com/pubfig.engine.js — 200 — 140.2 KiB — 135 ms — h3https://www.paypal.com/tagmanager/pptm.js?id=calibre-ebook.com&source=checkoutjs&t=xo&v=4.0.344www.paypal.com/tagmanager/pptm.js?i... https://www.paypal.com/tagmanager/pptm.js?id=calibre-ebook.com&source=checkoutjs&t=xo&v=4.0.344 — 200 — 1.7 KiB — 38 ms — h2https://c.pub.network/v2/cc.pub.network/v2/c https://c.pub.network/v2/c — 200 — 111 B — 46 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 — 75.9 KiB — 64 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_a99ef620ee_mjm6mtc6mdk&buttonSessionID=uid_7a0a3185ed_mjm6mtc6mdk&renderedButtons=paypal&storageID=uid_eeafe80593_mjm6mtc6mdk&funding.disallowed=venmo&logLevel=warn&sdkMeta=eyJ1cmwiOiJodHRwczovL3d3dy5wYXlwYWxvYmplY3RzLmNvbS9hcGkvY2hlY2tvdXQubWluLmpzIn0&uid=34b4a6b746&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_a99ef620ee_mjm6mtc6mdk&buttonSessionID=uid_7a0a3185ed_mjm6mtc6mdk&renderedButtons=paypal&storageID=uid_eeafe80593_mjm6mtc6mdk&funding.disallowed=venmo&logLevel=warn&sdkMeta=eyJ1cmwiOiJodHRwczovL3d3dy5wYXlwYWxvYmplY3RzLmNvbS9hcGkvY2hlY2tvdXQubWluLmpzIn0&uid=34b4a6b746&version=min&xcomponent=1 — 200 — 14.7 KiB — 361 ms — h2https://www.paypal.com/xoplatform/logger/api/loggerwww.paypal.com/xoplatform/logger/ap... https://www.paypal.com/xoplatform/logger/api/logger — 204 — 0 B — 243 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 — 5.2 KiB — 21 ms — h2https://www.paypal.com/tagmanager/pptm.js?client_id=AbVJy1AqjPTncpdEQteWqVN-DdULUR9vtpvEKQMAof4SFoiuiuAACRd0fjNvvTsZPnQy3Enai5lmdm1A&id=calibre-ebook.com&source=checkoutjs&t=xo&v=4.0.344www.paypal.com/tagmanager/pptm.js?c... https://www.paypal.com/tagmanager/pptm.js?client_id=AbVJy1AqjPTncpdEQteWqVN-DdULUR9vtpvEKQMAof4SFoiuiuAACRd0fjNvvTsZPnQy3Enai5lmdm1A&id=calibre-ebook.com&source=checkoutjs&t=xo&v=4.0.344 — 410 — 1.7 KiB — 336 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 — 31 ms — h2https://visit-server.inmobi-choice.io/visit-eventvisit-server.inmobi-choice.io/visit... https://visit-server.inmobi-choice.io/visit-event — 200 — 0 B — 139 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 — 19 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 — 80 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 — 0 B — 9 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 — 28 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 — 27 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 — 233 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%22pc%22%2C%22cmpPlatform%22%3A%22Mac%20OS%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%3A1776899830272%2C%22operationType%22%3A%22init%22%2C%22sessionId%22%3A%22GDPR-aqgle3i5tzimwzno9vo1%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%22pc%22%2C%22cmpPlatform%22%3A%22Mac%20OS%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%3A1776899830272%2C%22operationType%22%3A%22init%22%2C%22sessionId%22%3A%22GDPR-aqgle3i5tzimwzno9vo1%22%7D — 200 — 101 B — 129 ms — h2https://cmp.inmobi.com/geoipcmp.inmobi.com/geoip https://cmp.inmobi.com/geoip — 200 — 329 B — 19 ms — h2https://www.paypalobjects.com/api/checkout.min.jswww.paypalobjects.com/api/checkout.... https://www.paypalobjects.com/api/checkout.min.js — 200 — 169.2 KiB — 131 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 — 130 ms — h3data: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/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 — 537 B — 21 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 — 96 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/v1/oauth2/tokenwww.paypal.com/v1/oauth2/token https://www.paypal.com/v1/oauth2/token — 200 — 1.0 KiB — 251 ms — h2https://www.paypal.com/smart/api/button/funding?buttonLabel=pay&buttonSessionID=uid_7a0a3185ed_mjm6mtc6mdk&country=US&disallowed=venmo&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_7a0a3185ed_mjm6mtc6mdk&country=US&disallowed=venmo&domain=calibre-ebook.com&lang=en&renderedButtons=paypal — 200 — 2.4 KiB — 337 ms — h2https://www.paypal.com/xoplatform/logger/api/loggerwww.paypal.com/xoplatform/logger/ap... https://www.paypal.com/xoplatform/logger/api/logger — 200 — 1.6 KiB — 223 ms — h2https://calibre-ebook.com/favicon.png/favicon.png https://calibre-ebook.com/favicon.png — 200 — 16.6 KiB — 96 ms — h2https://www.paypal.com/xoplatform/logger/api/loggerwww.paypal.com/xoplatform/logger/ap... https://www.paypal.com/xoplatform/logger/api/logger — 200 — 2.1 KiB — 222 ms — h2https://www.paypal.com/graphql?GetNativeEligibilitywww.paypal.com/graphql?GetNativeEli... https://www.paypal.com/graphql?GetNativeEligibility — 200 — 2.1 KiB — 286 ms — h2https://www.paypal.com/xoplatform/logger/api/loggerwww.paypal.com/xoplatform/logger/ap... https://www.paypal.com/xoplatform/logger/api/logger — 200 — 2.4 KiB — 215 ms — h2
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
84% of JavaScript execution is third-party
First-party Third-party 577ms · 937KB · €6/mo
cmp.inmobi.com
Other
Optional
Execution 130ms
Transfer 116 KB
Unused 49%
Monthly Cost €1/mo
cmp.inmobi.com
Other
Optional
Execution 113ms
Transfer 125 KB
Unused 48%
Monthly Cost €1/mo
www.paypalobjects.com
Other
Optional
Execution 91ms
Transfer 169 KB
Unused 34%
Monthly Cost €1/mo
Unattributable
Other
Optional
Execution 75ms
Transfer 0 KB
Monthly Cost €1/mo
Google Tag Manager
Tag Manager
Optional
Execution 62ms
Transfer 154 KB
Unused 50%
Monthly Cost €1/mo
securepubads.g.doubleclick.net
Other
Optional
Execution 56ms
Transfer 188 KB
Unused 77%
Monthly Cost €1/mo
a.pub.network
Other
Optional
Execution 50ms
Transfer 184 KB
Unused 82%
Monthly Cost €1/mo

84% 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

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

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

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

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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