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https://iwm.org.uk

Performance

· 17 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
90
GRADE
A
FIX
2
REVIEW
1
PASS
12
INFO
2

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

Mobile Desktop
75
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.

927 ms

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

2.73 s

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

958 ms

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.

971 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.

3.15 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
12 PASS 1 REVIEW 2 FIX
D
Third-Party Impact
Action
80% third-party, 0 ms blocking
FIX
80% third-party, 0 ms blocking
Warning::
Third-party code accounts for 80% of page weight (402.9 KiB of 500.6 KiB)
Info::
Third-party blocking time is low (0 ms)
20%
80%
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
1661ms total JS execution
REVIEW
1661ms total JS execution
Warning::
https://iwm.org.uk/cdn-cgi/challenge-platform/h/b/...: 1384ms CPU time
Info::
Unattributable: 165ms CPU time
Info::
https://iwm.org.uk/: 113ms CPU time
Info::
Third-party scripts: 165ms (10% of total)

Main Thread Breakdown

Script Evaluation 80% Other 13%
ScriptTotalScriptingParse/CompileParty
https://iwm.org.uk/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9f07f254d815af351384ms1318ms25ms1st
Unattributable165ms5ms0ms3rd
https://iwm.org.uk/113ms13ms2ms1st
A+
Page Weight Budget
501 KB transferred, 20 requests
PASS
501 KB transferred, 20 requests
Info::
Page weighs 901 KB (501 KB transferred)
Info::
20 HTTP requests
Info::
Estimated 0.10 g CO2 per page load
501 KB / 2.4 MB budget
501 KB transferred
20 requests
0.10 g CO2 per page load
Other 294.0 KiB 59%
HTML 100.4 KiB 20%
JavaScript 89.7 KiB 18%
Images 11.4 KiB 2%
Other 3.4 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 11 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
10 scripts, 0 KB unused
PASS
10 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=9f07f254d815af3572 KB—✓1st
blob:https://iwm.org.uk/0afa6059-1fc0-4940-9aa9-972925e4c03c0 KB—✓3rd
https://challenges.cloudflare.com/turnstile/v0/b/0b8fb825cb67/api.js?onload=cFRiY3&render=explicit17 KB—✓3rd
blob:https://iwm.org.uk/6ead8291-64a7-4843-9903-68089fbb4ef2-0 KB—✓3rd
blob:https://challenges.cloudflare.com/27924e5b-2591-4e24-a380-a17cfd06510b0 KB—✓3rd
blob:https://challenges.cloudflare.com/4323c544-3cba-47b5-9917-1edfc0327a77-0 KB—✓3rd
blob:https://challenges.cloudflare.com/4323c544-3cba-47b5-9917-1edfc0327a77-0 KB—✓3rd
blob:https://challenges.cloudflare.com/4323c544-3cba-47b5-9917-1edfc0327a77-0 KB—✓3rd
blob:https://challenges.cloudflare.com/4323c544-3cba-47b5-9917-1edfc0327a77-0 KB—✓3rd
blob:https://challenges.cloudflare.com/4323c544-3cba-47b5-9917-1edfc0327a77-0 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
20 resources · 501 KB · 0 KB savings available
PASS
20 resources · 501 KB · 0 KB savings available
Info::
Within 1MB page-weight target
Got: 501 KB
Warning::
14 third-party resources (80% of weight)
Info::
1 resources over 200KB
20 resources · 500.6 KiB · 14 third-party Within 1MB page-weight target
Other 59% · 295.8 KiB
Document 21% · 103.7 KiB
JavaScript 18% · 89.7 KiB
Image 2% · 11.4 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
20 requests over 1580ms
INFO
0 ms 500 ms 1.0 s 1.5 s 2.0 s 2.5 s FCP 927 ms LCP 2.7 shttps://iwm.org.uk// https://iwm.org.uk/ — 307 — 60 B — 30 ms — http/1.1https://iwm.org.uk// https://iwm.org.uk/ — 403 — 3.3 KiB — 10 ms — h2https://iwm.org.uk/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9f07f254d815af35/cdn-cgi/challenge-platform/h/b/orc... https://iwm.org.uk/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9f07f254d815af35 — 200 — 72.3 KiB — 26 ms — h2blob:https://iwm.org.uk/0afa6059-1fc0-4940-9aa9-972925e4c03ciwm.org.uk/0afa6059-1fc0-4940-9aa9-... blob:https://iwm.org.uk/0afa6059-1fc0-4940-9aa9-972925e4c03c — -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 — 20 ms — h3https://iwm.org.uk/favicon.ico/favicon.ico https://iwm.org.uk/favicon.ico — 403 — 5.3 KiB — 10 ms — h2https://iwm.org.uk/favicon.ico/favicon.ico https://iwm.org.uk/favicon.ico — 403 — 3.3 KiB — 9 ms — h2https://iwm.org.uk/cdn-cgi/challenge-platform/h/b/flow/ov1/927531819:1776892371:vVewUlFmas0srb30l10YFlK8gjcJmXL29Dq7B946IKw/9f07f254d815af35/5G2v4Aj9mHkkzdBgwaMZ1aAXqqDoFQUA6hoV7I9D_0o-1776895701-1.2.1.1-IMlfe4qS5ShxDaBI5EYurFW.KfOh2..Utq9mJDvkYl0RTep2mdsbDf2y..3rtOzz/cdn-cgi/challenge-platform/h/b/flo... https://iwm.org.uk/cdn-cgi/challenge-platform/h/b/flow/ov1/927531819:1776892371:vVewUlFmas0srb30l10YFlK8gjcJmXL29Dq7B946IKw/9f07f254d815af35/5G2v4Aj9mHkkzdBgwaMZ1aAXqqDoFQUA6hoV7I9D_0o-1776895701-1.2.1.1-IMlfe4qS5ShxDaBI5EYurFW.KfOh2..Utq9mJDvkYl0RTep2mdsbDf2y..3rtOzz — 200 — 13.5 KiB — 30 ms — h2blob:https://iwm.org.uk/6ead8291-64a7-4843-9903-68089fbb4ef2iwm.org.uk/6ead8291-64a7-4843-9903-... blob:https://iwm.org.uk/6ead8291-64a7-4843-9903-68089fbb4ef2 — 200 — -1 B — 28 ms — blobhttps://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/turnstile/f/ov2/av0/rch/cxu6d/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/cxu6d/0x4AAAAAAADnPIDROrmt1Wwj/light/fbE/new/normal?lang=auto — 200 — 97.1 KiB — 35 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 — 7 ms — h3blob:https://challenges.cloudflare.com/27924e5b-2591-4e24-a380-a17cfd06510bchallenges.cloudflare.com/27924e5b-... blob:https://challenges.cloudflare.com/27924e5b-2591-4e24-a380-a17cfd06510b — -1 — 0 B — 0 ms — https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/flow/ov1/4100900095:1776892373:L0nL67ly3l9VisnM33R_sKjYxQhSpF0B3njDgeQGRpI/9f07f2575d06f264/SVlDucbZi2Vyg7cN8ldIVy0L_UKexbdxtQXd59DsK8s-1776895701-1.2.1.1-aj4o_qRopY0QhqYBYCs1b.7y3tQMjEHT1sFcZ3PD0pT5csapzhV_0ZazbvVxUv.schallenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/flow/ov1/4100900095:1776892373:L0nL67ly3l9VisnM33R_sKjYxQhSpF0B3njDgeQGRpI/9f07f2575d06f264/SVlDucbZi2Vyg7cN8ldIVy0L_UKexbdxtQXd59DsK8s-1776895701-1.2.1.1-aj4o_qRopY0QhqYBYCs1b.7y3tQMjEHT1sFcZ3PD0pT5csapzhV_0ZazbvVxUv.s — 200 — 280.6 KiB — 111 ms — h3blob:https://challenges.cloudflare.com/4323c544-3cba-47b5-9917-1edfc0327a77challenges.cloudflare.com/4323c544-... blob:https://challenges.cloudflare.com/4323c544-3cba-47b5-9917-1edfc0327a77 — 200 — -1 B — 23 ms — blobblob:https://challenges.cloudflare.com/4323c544-3cba-47b5-9917-1edfc0327a77challenges.cloudflare.com/4323c544-... blob:https://challenges.cloudflare.com/4323c544-3cba-47b5-9917-1edfc0327a77 — 200 — -1 B — 23 ms — blobblob:https://challenges.cloudflare.com/4323c544-3cba-47b5-9917-1edfc0327a77challenges.cloudflare.com/4323c544-... blob:https://challenges.cloudflare.com/4323c544-3cba-47b5-9917-1edfc0327a77 — 200 — -1 B — 25 ms — blobblob:https://challenges.cloudflare.com/4323c544-3cba-47b5-9917-1edfc0327a77challenges.cloudflare.com/4323c544-... blob:https://challenges.cloudflare.com/4323c544-3cba-47b5-9917-1edfc0327a77 — 200 — -1 B — 27 ms — blobblob:https://challenges.cloudflare.com/4323c544-3cba-47b5-9917-1edfc0327a77challenges.cloudflare.com/4323c544-... blob:https://challenges.cloudflare.com/4323c544-3cba-47b5-9917-1edfc0327a77 — 200 — -1 B — 40 ms — blobhttps://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/pat/9f07f2575d06f264/1776895701980/d4fbee959139005f89b6d4bcc3f20f6d5fd347b904e94658b31b366c4810cb03/7Xmb3BexyqKs1Zlchallenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/pat/9f07f2575d06f264/1776895701980/d4fbee959139005f89b6d4bcc3f20f6d5fd347b904e94658b31b366c4810cb03/7Xmb3BexyqKs1Zl — 401 — 1.7 KiB — 7 ms — h3https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/d/9f07f2575d06f264/1776895701980/VUGFdkZ0tAdAjfJchallenges.cloudflare.com/cdn-cgi/c... https://challenges.cloudflare.com/cdn-cgi/challenge-platform/h/b/d/9f07f2575d06f264/1776895701980/VUGFdkZ0tAdAjfJ — 200 — 5.9 KiB — 7 ms — h3
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 165ms · 0KB · £2/mo
Unattributable
Other
Optional
Execution 165ms
Transfer 0 KB
Monthly Cost £2/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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