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Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
91
GRADE
A
FIX
2
REVIEW
1
PASS
12
INFO
2

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

Mobile Desktop
69
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
90
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.
40
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.

924 ms

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

3.19 s

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

1.21 s

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

0.003

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

944 ms

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

3.59 s

Page Load Progression

418 ms
837 ms
1.3 s
1.7 s
2.1 s
2.5 s
2.9 s
3.3 s
Checks
17
12 PASS 1 REVIEW 2 FIX
D
Third-Party Impact
Action
82% third-party, 0 ms blocking
FIX
82% third-party, 0 ms blocking
Warning::
Third-party code accounts for 82% of page weight (412.8 KiB of 502.9 KiB)
Info::
Third-party blocking time is low (0 ms)
18%
82%
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
1974ms total JS execution
REVIEW
1974ms total JS execution
Warning::
https://packtpub.com/cdn-cgi/challenge-platform/h/...: 1662ms CPU time
Info::
Unattributable: 216ms CPU time
Info::
https://packtpub.com/: 96ms CPU time
Info::
Third-party scripts: 216ms (11% of total)

Main Thread Breakdown

Script Evaluation 81% Other 11% Garbage Collection 3%
ScriptTotalScriptingParse/CompileParty
https://packtpub.com/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9f087fcb1c9a45681662ms1583ms26ms1st
Unattributable216ms8ms0ms3rd
https://packtpub.com/96ms11ms2ms1st
A+
Page Weight Budget
503 KB transferred, 22 requests
PASS
503 KB transferred, 22 requests
Info::
Page weighs 909 KB (503 KB transferred)
Info::
22 HTTP requests
Info::
Estimated 0.10 g CO2 per page load
503 KB / 2.4 MB budget
503 KB transferred
22 requests
0.10 g CO2 per page load
Other 307.8 KiB 61%
HTML 101.4 KiB 20%
JavaScript 90.1 KiB 18%
Other 1.7 KiB 0%
Images 1.4 KiB 0%
Other 560 B 0%
0 2.4 MB 4.9 MB
Under budget
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
3 images, 0 KB saveable
PASS
3 images, 0 KB saveable
Info::
All images are well-optimized
3 images 1 KB
0 oversized -0 KB
2 legacy format
0 missing dimensions CLS risk
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+
JS Bundles
9 scripts, 0 KB unused
PASS
9 scripts, 0 KB unused
0 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://packtpub.com/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9f087fcb1c9a456873 KB—✓1st
blob:https://packtpub.com/1c088fa5-43f1-4756-ad4f-bbd9682d16d40 KB—✓3rd
https://challenges.cloudflare.com/turnstile/v0/b/0b8fb825cb67/api.js?onload=cFRiY3&render=explicit17 KB—✓3rd
blob:https://packtpub.com/0ecd96bf-f64d-4b2a-9a70-b338d4fdc6de-0 KB—✓3rd
blob:https://challenges.cloudflare.com/9e0272c9-df9a-4295-b130-3bcbed1c91380 KB—✓3rd
blob:https://challenges.cloudflare.com/d73281c3-7cf6-4704-8af1-0ffba114ff3c-0 KB—✓3rd
blob:https://challenges.cloudflare.com/d73281c3-7cf6-4704-8af1-0ffba114ff3c-0 KB—✓3rd
blob:https://challenges.cloudflare.com/d73281c3-7cf6-4704-8af1-0ffba114ff3c-0 KB—✓3rd
blob:https://challenges.cloudflare.com/d73281c3-7cf6-4704-8af1-0ffba114ff3c0 KB—✓3rd
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
22 resources · 503 KB · 0 KB savings available
PASS
22 resources · 503 KB · 0 KB savings available
Info::
Within 1MB page-weight target
Got: 503 KB
Warning::
15 third-party resources (82% of weight)
Info::
1 resources over 200KB
22 resources · 502.9 KiB · 15 third-party Within 1MB page-weight target
Other 62% · 310.0 KiB
Document 20% · 101.4 KiB
JavaScript 18% · 90.1 KiB
Image 0% · 1.4 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
22 requests over 3260ms
INFO
0 ms 1.0 s 2.0 s 3.0 s FCP 924 ms LCP 3.2 shttps://packtpub.com// https://packtpub.com/ — 307 — 62 B — 31 ms — http/1.1https://packtpub.com// https://packtpub.com/ — 403 — 3.3 KiB — 12 ms — h2https://packtpub.com/cdn-cgi/speculation/cdn-cgi/speculation https://packtpub.com/cdn-cgi/speculation — 200 — 320 B — 8 ms — h3https://packtpub.com/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9f087fcb1c9a4568/cdn-cgi/challenge-platform/h/b/orc... https://packtpub.com/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9f087fcb1c9a4568 — 200 — 72.7 KiB — 24 ms — h3blob:https://packtpub.com/1c088fa5-43f1-4756-ad4f-bbd9682d16d4packtpub.com/1c088fa5-43f1-4756-ad4... blob:https://packtpub.com/1c088fa5-43f1-4756-ad4f-bbd9682d16d4 — -1 — 0 B — 0 ms — https://challenges.cloudflare.com/turnstile/v0/b/0b8fb825cb67/api.js?onload=cFRiY3&render=explicitchallenges.cloudflare.com/turnstile... https://challenges.cloudflare.com/turnstile/v0/b/0b8fb825cb67/api.js?onload=cFRiY3&render=explicit — 200 — 17.4 KiB — 25 ms — h3https://packtpub.com/favicon.ico/favicon.ico https://packtpub.com/favicon.ico — 301 — 178 B — 9 ms — h3https://www.packtpub.com/favicon.icowww.packtpub.com/favicon.ico https://www.packtpub.com/favicon.ico — -1 — 0 B — 26 ms — https://packtpub.com/favicon.ico/favicon.ico https://packtpub.com/favicon.ico — 301 — 0 B — 1 ms — h3https://www.packtpub.com/favicon.icowww.packtpub.com/favicon.ico https://www.packtpub.com/favicon.ico — -1 — 0 B — 15 ms — https://packtpub.com/cdn-cgi/challenge-platform/h/b/flow/ov1/921088994:1776899606:TCZPLuqASM5Jf1BRi0FqA4kltO4BdQiE46Zi5nq76HU/9f087fcb1c9a4568/RrMgdGhlJGZnEzee9D_3y1T_SWHZo67R1xzISkvn6HU-1776901495-1.2.1.1-ftSFWNP.OGzapS0bynlE1PbhFAXCYQc6Jv6S6Dh.GKWTs3UhigxAONwfRU.jafi0/cdn-cgi/challenge-platform/h/b/flo... https://packtpub.com/cdn-cgi/challenge-platform/h/b/flow/ov1/921088994:1776899606:TCZPLuqASM5Jf1BRi0FqA4kltO4BdQiE46Zi5nq76HU/9f087fcb1c9a4568/RrMgdGhlJGZnEzee9D_3y1T_SWHZo67R1xzISkvn6HU-1776901495-1.2.1.1-ftSFWNP.OGzapS0bynlE1PbhFAXCYQc6Jv6S6Dh.GKWTs3UhigxAONwfRU.jafi0 — 200 — 13.5 KiB — 24 ms — h3blob:https://packtpub.com/0ecd96bf-f64d-4b2a-9a70-b338d4fdc6depacktpub.com/0ecd96bf-f64d-4b2a-9a7... blob:https://packtpub.com/0ecd96bf-f64d-4b2a-9a70-b338d4fdc6de — 200 — -1 B — 49 ms — blobhttps://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/turnstile/f/ov2/av0/rch/jxqfg/0x4AAAAAAADnPIDROrmt1Wwj/light/fbE/new/normal?lang=autochallenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/turnstile/f/ov2/av0/rch/jxqfg/0x4AAAAAAADnPIDROrmt1Wwj/light/fbE/new/normal?lang=auto — 200 — 98.1 KiB — 38 ms — h3https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/cmg/1challenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/cmg/1 — 200 — 208 B — 6 ms — h3blob:https://challenges.cloudflare.com/9e0272c9-df9a-4295-b130-3bcbed1c9138challenges.cloudflare.com/9e0272c9-... blob:https://challenges.cloudflare.com/9e0272c9-df9a-4295-b130-3bcbed1c9138 — -1 — 0 B — 0 ms — https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/flow/ov1/859148713:1776899608:oBD1f9EvGn7UNBmE1Cfjd9Pm5Z3I3dGjHCcQ4LeOxkM/9f087fcd8acd2496/oz8OPssoNupLvjrSgLGSiTYkaVONqoXl9Brs9cSKSxQ-1776901495-1.2.1.1-Zu2EYQQuiI4dB9hJFPN0hy25PQWM0eEXRjz5_LBfOVJMXof4mNCKSDdq0Ha6iP0Dchallenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/flow/ov1/859148713:1776899608:oBD1f9EvGn7UNBmE1Cfjd9Pm5Z3I3dGjHCcQ4LeOxkM/9f087fcd8acd2496/oz8OPssoNupLvjrSgLGSiTYkaVONqoXl9Brs9cSKSxQ-1776901495-1.2.1.1-Zu2EYQQuiI4dB9hJFPN0hy25PQWM0eEXRjz5_LBfOVJMXof4mNCKSDdq0Ha6iP0D — 200 — 294.3 KiB — 135 ms — h3blob:https://challenges.cloudflare.com/d73281c3-7cf6-4704-8af1-0ffba114ff3cchallenges.cloudflare.com/d73281c3-... blob:https://challenges.cloudflare.com/d73281c3-7cf6-4704-8af1-0ffba114ff3c — 200 — -1 B — 28 ms — blobhttps://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/pat/9f087fcd8acd2496/1776901496286/2e9054586db51756391d7e41d5af4831779bd09421b68f1e5c8a7275b3611063/MdNJkUPK08raXHqchallenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/pat/9f087fcd8acd2496/1776901496286/2e9054586db51756391d7e41d5af4831779bd09421b68f1e5c8a7275b3611063/MdNJkUPK08raXHq — 401 — 1.7 KiB — 10 ms — h3blob:https://challenges.cloudflare.com/d73281c3-7cf6-4704-8af1-0ffba114ff3cchallenges.cloudflare.com/d73281c3-... blob:https://challenges.cloudflare.com/d73281c3-7cf6-4704-8af1-0ffba114ff3c — 200 — -1 B — 24 ms — blobblob:https://challenges.cloudflare.com/d73281c3-7cf6-4704-8af1-0ffba114ff3cchallenges.cloudflare.com/d73281c3-... blob:https://challenges.cloudflare.com/d73281c3-7cf6-4704-8af1-0ffba114ff3c — 200 — -1 B — 21 ms — blobblob:https://challenges.cloudflare.com/d73281c3-7cf6-4704-8af1-0ffba114ff3cchallenges.cloudflare.com/d73281c3-... blob:https://challenges.cloudflare.com/d73281c3-7cf6-4704-8af1-0ffba114ff3c — -1 — 0 B — 0 ms — https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/d/9f087fcd8acd2496/1776901496291/2WW6ekt3Lk4SgL3challenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/d/9f087fcd8acd2496/1776901496291/2WW6ekt3Lk4SgL3 — 200 — 1.2 KiB — 6 ms — h3
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
11% of JavaScript execution is third-party
First-party Third-party 216ms · 0KB · $3/mo
Unattributable
Other
Costly
Execution 216ms
Transfer 0 KB
Monthly Cost $3/mo

These scripts may cost more than they're worth

  • Unattributable adds 216ms and costs ~$3/month

Unattributable takes 216ms 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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