londoncss.dev
Ranks Overall #1,478 Built Awesome #992
Data from Oct 5, 2026, 11:50 PM UTC old Measured once a week · 7 runs since Aug 21, 2026
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Lab data is measured using Lighthouse, Mobile mode unless otherwise specified. Field data is reported from Chrome UX Report (using p75 measurements).
Stack
Uses
Lit 3.3.3
ES
Hosted by
ESF
Lighthouse Scores LAB Simulated
61
Performance
↓ -7 (-10.3%)
100
Accessibility
no change
96
Best Practices
no change
90
SEO
no change
Metrics LAB
No field data: the Chrome UX Report is not being collected for this project, so every figure below is from the Lighthouse run.
| Metric | Lab Simulated | ||
|---|---|---|---|
| Value | Change / range | Trend | |
| LCP CWV (estimate) Largest Contentful Paint | 5.09 s poor | ↑ +1059 ms (+26.3%) 4.03 s – 7.35 s | |
| INP CWV Interaction to Next Paint — field only, no lab run can measure it | n/a | — | |
| CLS CWV (estimate) Cumulative Layout Shift | 0.001 good | → no change 0 – 0.001 | |
| TBT Total Blocking Time | 338 ms needs work | ↓ -47 ms (-12.2%) 222 ms – 385 ms | |
| FCP First Contentful Paint | 5.09 s poor | ↑ +1059 ms (+26.3%) 4.03 s – 5.10 s | |
| Speed Index | 5.09 s needs work | ↑ +1059 ms (+26.3%) 4.03 s – 5.10 s | |
| TTFB Time to First Byte | 693 ms good | ↑ +43 ms (+6.6%) 649 ms – 711 ms | |
LCP Subparts LAB Unthrottled
The subparts attribute LCP to your server, resource discovery, download, or rendering. Note that the Lab LCP shown above is a simulated throttled estimate.
time to first byte
118 ms
element render delay
101 ms
Page weight
| Metric | Value | Change / range | Trend |
|---|---|---|---|
| Page Weight | 1.12 MB | ↑ +216.3 kB (+24.6%) significant 882 kB – 1.12 MB | |
| Requests | 23 | → no change 22 – 25 | |
| Third-party Weight | 1.08 MB | ↑ +215.7 kB (+25.8%) significant 840 kB – 1.08 MB | |
| Third-party CPU | 124 ms | ↓ -11 ms (-8.2%) significant 124 ms – 135 ms | |
| Unused JS | 447 kB | ↑ +156.5 kB (+55.9%) significant 284 kB – 447 kB | |
| Unused CSS | 222 kB | ↑ +4.8 kB (+2.3%) 203 kB – 222 kB |
By resource type
| Type | Transfer | Share | Size | Requests |
|---|---|---|---|---|
| script | 67.2% | 754 kB | 10 | |
| stylesheet | 20.5% | 230 kB | 4 | |
| font | 8.4% | 93.6 kB | 3 | |
| document | 3.9% | 43.2 kB | 1 | |
| other | 0.1% | 812 B | 5 | |
| Total | 1.12 MB | 23 |
Third parties 4 entities
| Entity | Transfer | Size | Main thread Simulated |
|---|---|---|---|
| Google CDN | 645 kB | 100 ms | |
| Other Google APIs/SDKs | 333 kB | 24 ms | |
| Google Fonts | 99.8 kB | 0 ms | |
| withgoogle.com | 317 B | 0 ms | |
| Total | 1.08 MB | 124 ms |
Page health
| Metric | Value | Change / range | Trend |
|---|---|---|---|
| Main Thread Work | 1.44 s | ↓ -58 ms (-3.9%) 1.40 s – 1.50 s | |
| Long Tasks | 8 | → no change 6 – 8 | |
| DOM Elements | 708 | → no change 649 – 708 | |
| Axe Violations Violating nodes from a full Axe CLI run (more than Lighthouse reports) | 34 | → no change 31 – 35 | |
| A11y Failures | 0 | → no change 0 – 0 | |
| A11y Failing Nodes | 0 | → no change 0 – 0 |
Main thread work
| Task | Time | Share | Duration Simulated |
|---|---|---|---|
| script evaluation | 41% | 584 ms | |
| other | 28% | 409 ms | |
| script parse compile | 12% | 173 ms | |
| style layout | 10% | 151 ms | |
| parse HTML | 5% | 69 ms | |
| paint composite render | 3% | 37 ms | |
| garbage collection | 1% | 19 ms | |
| Total | 1.44 s |
Axe violations axe-core 4.13.0, full rule set
34 violating nodes across 3 rules, 672 passing. This is a standalone Axe CLI run and is stricter than the subset Lighthouse already includes.
-
moderate
region— All page content should be contained by landmarks 32 nodesOffending elements (5 of 32)
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#h\.hrlmpx1ntmmo_l > .CjVfdc[jscontroller="Ae65rd"] > .C9DxTc<span class="C9DxTc " style="">Unleash the Power of Pure CSS at London in 2025</span> -
p:nth-child(3)<p dir="ltr" class="zfr3Q CDt4Ke " style=""><span class="C9DxTc " style="">Are you bending the limits of CSS? From intricate animations to mind-bending layouts, join a community of web designers who … -
p:nth-child(4)<p dir="ltr" class="zfr3Q CDt4Ke " style=""><span class="C9DxTc " style="">This isn’t just another dev meetup — it's a celebration of CSS as a creative medium. Whether you're pushing pixels with prec… -
#h\.3wnrad5o8me9_l > .CjVfdc[jscontroller="Ae65rd"] > .C9DxTc<span class="C9DxTc " style="">Why attend?</span> -
.n8H08c.UVNKR:nth-child(7)<ul class="n8H08c UVNKR " style="list-style-type: square; margin-left: 0; margin-right: 0; padding: 0;">
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moderate
landmark-no-duplicate-banner— Document should not have more than one banner landmark 1 nodeOffending element
-
div[jscontroller="RrXLpc"]<div jscontroller="RrXLpc" jsname="XeeWQc" role="banner" jsaction="keydown:uiKYid(OH0EC);rcuQ6b:WYd;zuqEgd:ufqpf;JIbuQc:XfTnxb(lfEfFf),AlTiYc(GeGHKb),AlTiYc(m1xNUe),zZlNMe(pZn8Oc);YqO5N:ELcyfe;">
-
-
moderate
landmark-unique— Landmarks should have a unique role or role/label/title (i.e. accessible name) combination 1 nodeOffending element
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div[jscontroller="RrXLpc"]<div jscontroller="RrXLpc" jsname="XeeWQc" role="banner" jsaction="keydown:uiKYid(OH0EC);rcuQ6b:WYd;zuqEgd:ufqpf;JIbuQc:XfTnxb(lfEfFf),AlTiYc(GeGHKb),AlTiYc(m1xNUe),zZlNMe(pZn8Oc);YqO5N:ELcyfe;">
-
Best Practices failures 1 of 17 audits
-
errors-in-console— Browser errors were logged to the console 2 items
SEO failures 1 of 7 audits
-
meta-description— Document does not have a meta description
Hygiene
HTTPS
HSTS
CSP
Clickjacking protection
Origin isolation
Trusted Types
bfcache
h2
2 console errors
Measurement log
Every stored run for this URL, newest first.
| When | Scores | Perf | LCP | CLS | TBT | Weight | Runs | Spread | Bench | Took | Archive |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Oct 5, 2026, 11:50 PM UTC | 61 | 5.09 s | 0.001 | 338 ms | 1.12 MB | 3/3 | ±25 | 2,505 +1% | 28s |
|
|
| Sep 28, 2026, 6:29 PM UTC | 68 | 4.03 s | 0.001 | 385 ms | 900 kB | 3/3 | ±15 | 2,488 0% | 28.8s |
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|
| Sep 21, 2026, 2:52 PM UTC | 58 | 7.35 s | 0.001 | 258 ms | 894 kB | 3/3 | ±5 | 2,442 -2% | 29s |
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|
| Sep 14, 2026, 11:54 AM UTC | 60 | 5.08 s | 0.001 | 367 ms | 981 kB | 3/3 | ±13 | 2,473 -1% | 29.9s |
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| Sep 7, 2026, 8:57 AM UTC | 64 | 5.10 s | 0 | 345 ms | 886 kB | 3/3 | ±11 | 2,356 -5% | 28.1s |
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| Aug 31, 2026, 3:52 AM UTC | 61 | 5.05 s | 0.001 | 358 ms | 885 kB | 3/3 | ±17 | 2,494 0% | 30.6s |
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| Aug 21, 2026, 1:47 PM UTC | 60 | 7.24 s | 0.001 | 222 ms | 882 kB | 3/3 | ±6 | 2,482 0% | 29s |
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