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https://iwm.org.uk

Performance

· 15 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
90
GRADE
A
FIX
2
REVIEW
1
PASS
10
INFO
2

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

Mobile Desktop
100
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.
96
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.

255 ms

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

764 ms

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

52 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.

385 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.

771 ms

Page Load Progression

472 ms
943 ms
1.4 s
1.9 s
2.4 s
2.8 s
3.3 s
3.8 s
Checks
15
10 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 (421.3 KiB of 516.4 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.

B
JS Execution Cost
559ms total JS execution
REVIEW
559ms total JS execution
Warning::
https://iwm.org.uk/cdn-cgi/challenge-platform/h/b/...: 506ms CPU time
Info::
Unattributable: 54ms CPU time
Info::
Third-party scripts: 54ms (10% of total)

Main Thread Breakdown

Script Evaluation 83% Other 10%
ScriptTotalScriptingParse/CompileParty
https://iwm.org.uk/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9f07f2a9afe9e638506ms490ms6ms1st
Unattributable54ms4ms0ms3rd
A+
Page Weight Budget
516 KB transferred, 19 requests
PASS
516 KB transferred, 19 requests
Info::
Page weighs 916 KB (516 KB transferred)
Info::
19 HTTP requests
Info::
Estimated 0.11 g CO2 per page load
516 KB / 2.4 MB budget
516 KB transferred
19 requests
0.11 g CO2 per page load
Other 319.4 KiB 62%
HTML 97.9 KiB 19%
JavaScript 87.2 KiB 17%
Images 7.0 KiB 1%
Other 3.3 KiB 1%
Other 1.7 KiB 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 7 KB
0 oversized -0 KB
3 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
8 scripts, 0 KB unused
PASS
8 scripts, 0 KB unused
0 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://iwm.org.uk/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9f07f2a9afe9e63870 KB—✓1st
blob:https://iwm.org.uk/a890fe66-a10b-4a5e-a602-7287991709cf0 KB—✓3rd
https://challenges.cloudflare.com/turnstile/v0/b/0b8fb825cb67/api.js?onload=cFRiY3&render=explicit17 KB—✓3rd
blob:https://iwm.org.uk/5be8299a-36e8-46ef-982c-3445f28d21a4-0 KB—✓3rd
blob:https://challenges.cloudflare.com/1c3b2418-6a7d-43eb-ad5b-35e20e287e7f0 KB—✓3rd
blob:https://challenges.cloudflare.com/fe48191c-1f13-49ba-87a6-e2cd0da764d4-0 KB—✓3rd
blob:https://challenges.cloudflare.com/fe48191c-1f13-49ba-87a6-e2cd0da764d4-0 KB—✓3rd
blob:https://challenges.cloudflare.com/49412f3b-a242-43e0-b36d-36f45b4f1638-0 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
19 resources · 516 KB · 0 KB savings available
PASS
19 resources · 516 KB · 0 KB savings available
Info::
Within 1MB page-weight target
Got: 516 KB
Warning::
13 third-party resources (82% of weight)
Info::
1 resources over 200KB
19 resources · 516.4 KiB · 13 third-party Within 1MB page-weight target
Other 62% · 321.1 KiB
Document 20% · 101.2 KiB
JavaScript 17% · 87.2 KiB
Image 1% · 7.0 KiB
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
19 requests over 3345ms
INFO
0 ms 1.0 s 2.0 s 3.0 s FCP 255 ms LCP 764 mshttps://iwm.org.uk// https://iwm.org.uk/ — 307 — 60 B — 22 ms — http/1.1https://iwm.org.uk// https://iwm.org.uk/ — 403 — 3.3 KiB — 7 ms — h2https://iwm.org.uk/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9f07f2a9afe9e638/cdn-cgi/challenge-platform/h/b/orc... https://iwm.org.uk/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9f07f2a9afe9e638 — 200 — 69.8 KiB — 21 ms — h2blob:https://iwm.org.uk/a890fe66-a10b-4a5e-a602-7287991709cfiwm.org.uk/a890fe66-a10b-4a5e-a602-... blob:https://iwm.org.uk/a890fe66-a10b-4a5e-a602-7287991709cf — -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 — 17.3 KiB — 25 ms — h3https://iwm.org.uk/favicon.ico/favicon.ico https://iwm.org.uk/favicon.ico — 403 — 5.2 KiB — 11 ms — h2https://iwm.org.uk/favicon.ico/favicon.ico https://iwm.org.uk/favicon.ico — 403 — 3.3 KiB — 11 ms — h2https://iwm.org.uk/cdn-cgi/challenge-platform/h/b/flow/ov1/927531819:1776892371:vVewUlFmas0srb30l10YFlK8gjcJmXL29Dq7B946IKw/9f07f2a9afe9e638/SvSebqNQOZQUgShJmfhr8Nqw0UBBeK0SPitXcho.Db0-1776895714-1.2.1.1-PyTVrnvkHj6r3MWyKme0rjshbMDklsY_7YXm31oWe2bs_jgmwzkN9LKJIISm9T.p/cdn-cgi/challenge-platform/h/b/flo... https://iwm.org.uk/cdn-cgi/challenge-platform/h/b/flow/ov1/927531819:1776892371:vVewUlFmas0srb30l10YFlK8gjcJmXL29Dq7B946IKw/9f07f2a9afe9e638/SvSebqNQOZQUgShJmfhr8Nqw0UBBeK0SPitXcho.Db0-1776895714-1.2.1.1-PyTVrnvkHj6r3MWyKme0rjshbMDklsY_7YXm31oWe2bs_jgmwzkN9LKJIISm9T.p — 200 — 13.5 KiB — 20 ms — h2blob:https://iwm.org.uk/5be8299a-36e8-46ef-982c-3445f28d21a4iwm.org.uk/5be8299a-36e8-46ef-982c-... blob:https://iwm.org.uk/5be8299a-36e8-46ef-982c-3445f28d21a4 — 200 — -1 B — 40 ms — blobhttps://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/turnstile/f/ov2/av0/rch/qqun9/0x4AAAAAAADnPIDROrmt1Wwj/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/qqun9/0x4AAAAAAADnPIDROrmt1Wwj/light/fbE/new/normal?lang=auto — 200 — 94.6 KiB — 30 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/1c3b2418-6a7d-43eb-ad5b-35e20e287e7fchallenges.cloudflare.com/1c3b2418-... blob:https://challenges.cloudflare.com/1c3b2418-6a7d-43eb-ad5b-35e20e287e7f — -1 — 0 B — 0 ms — https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/flow/ov1/4100900095:1776892373:L0nL67ly3l9VisnM33R_sKjYxQhSpF0B3njDgeQGRpI/9f07f2abeb925f28/g3HOgUcyOgkxgUWC_rk3Rbbi2iJsGcTz0Xd22xQKKVA-1776895715-1.2.1.1-F.o9oGTXIp__dqTdCiCrDmjBeWopiGfdre9LWVe8Ok1DYaXlL2u1h.52FA4BRtpGchallenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/flow/ov1/4100900095:1776892373:L0nL67ly3l9VisnM33R_sKjYxQhSpF0B3njDgeQGRpI/9f07f2abeb925f28/g3HOgUcyOgkxgUWC_rk3Rbbi2iJsGcTz0Xd22xQKKVA-1776895715-1.2.1.1-F.o9oGTXIp__dqTdCiCrDmjBeWopiGfdre9LWVe8Ok1DYaXlL2u1h.52FA4BRtpG — 200 — 283.1 KiB — 124 ms — h3blob:https://challenges.cloudflare.com/fe48191c-1f13-49ba-87a6-e2cd0da764d4challenges.cloudflare.com/fe48191c-... blob:https://challenges.cloudflare.com/fe48191c-1f13-49ba-87a6-e2cd0da764d4 — 200 — -1 B — 92 ms — blobblob:https://challenges.cloudflare.com/fe48191c-1f13-49ba-87a6-e2cd0da764d4challenges.cloudflare.com/fe48191c-... blob:https://challenges.cloudflare.com/fe48191c-1f13-49ba-87a6-e2cd0da764d4 — 200 — -1 B — 19 ms — blobhttps://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/pat/9f07f2abeb925f28/1776895715529/28834a8156bd4005df4abefa3751383aeb25cb5db3861fc95f74f865341d489b/xxJrRh8_JmV2PgUchallenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/pat/9f07f2abeb925f28/1776895715529/28834a8156bd4005df4abefa3751383aeb25cb5db3861fc95f74f865341d489b/xxJrRh8_JmV2PgU — 401 — 1.7 KiB — 7 ms — h3https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/d/9f07f2abeb925f28/1776895715530/IhvtiFcsHMWvgxdchallenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/d/9f07f2abeb925f28/1776895715530/IhvtiFcsHMWvgxd — 200 — 1.6 KiB — 10 ms — h3https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/flow/ov1/4100900095:1776892373:L0nL67ly3l9VisnM33R_sKjYxQhSpF0B3njDgeQGRpI/9f07f2abeb925f28/g3HOgUcyOgkxgUWC_rk3Rbbi2iJsGcTz0Xd22xQKKVA-1776895715-1.2.1.1-F.o9oGTXIp__dqTdCiCrDmjBeWopiGfdre9LWVe8Ok1DYaXlL2u1h.52FA4BRtpGchallenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/flow/ov1/4100900095:1776892373:L0nL67ly3l9VisnM33R_sKjYxQhSpF0B3njDgeQGRpI/9f07f2abeb925f28/g3HOgUcyOgkxgUWC_rk3Rbbi2iJsGcTz0Xd22xQKKVA-1776895715-1.2.1.1-F.o9oGTXIp__dqTdCiCrDmjBeWopiGfdre9LWVe8Ok1DYaXlL2u1h.52FA4BRtpG — 200 — 22.8 KiB — 29 ms — h3blob:https://challenges.cloudflare.com/49412f3b-a242-43e0-b36d-36f45b4f1638challenges.cloudflare.com/49412f3b-... blob:https://challenges.cloudflare.com/49412f3b-a242-43e0-b36d-36f45b4f1638 — 200 — -1 B — 23 ms — blob
HTML JavaScript CSS Images Fonts XHR/Fetch Other
Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
10% of JavaScript execution is third-party
First-party Third-party 54ms · 0KB · £1/mo
Unattributable
Other
Optional
Execution 54ms
Transfer 0 KB
Monthly Cost £1/mo

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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