speedlify2

Lighthouse lab metrics, Axe, and Chrome UX Report field data for a list of sites recorded and compared over time. Follow us on Mastodon or Bluesky.

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worldwideweb.cern.ch

https://worldwideweb.cern.ch/

100PERF 80A11Y 100BEST 100SEO !AXE ✓CWV

Ranks Overall #930 Built Awesome #673

Data from Oct 5, 2026, 1:46 AM UTC old Measured once a week · 7 runs since Aug 21, 2026

Elsewhere: PageSpeed Insights · Calibre · Treo · CrUX Vis · Tame the Bots · Scoring Calculator · Wayback Machine

Lab data is measured using Lighthouse, Mobile mode unless otherwise specified. Field data is reported from Chrome UX Report (using p75 measurements).

Lighthouse Scores LAB Simulated

100
Performance
no change
80
Accessibility
no change
100
Best Practices
no change
100
SEO
no change

Metrics LAB FIELD

Core Web Vitals: passing 3 of 3 assessed from real Chrome users.

Field figures are the p75 across real Chrome users over a 28-day trailing window (2026-09-05 → 2026-10-02), url-level.

Metric Lab Simulated Field
Value Change / range Trend p75 Distribution
LCP CWV Largest Contentful Paint 977 ms good ↓ -2 ms (-0.2%) 977 ms – 2.17 s 2.28 s good 77.7% 13% 9.3%
INP CWV Interaction to Next Paint — field only, no lab run can measure it n/a — 102 ms good site-wide 89.5% 7.4% 3.2%
CLS CWV Cumulative Layout Shift 0 good → no change 0 – 0 0 good 90.5% 8.4% 1.1%
TBT Total Blocking Time 0 ms good → no change 0 ms – 102 ms n/a —
FCP First Contentful Paint 902 ms good ↓ -2 ms (-0.2%) 902 ms – 1.57 s 2.27 s needs work 65.2% 17.2% 17.6%
Speed Index 1.77 s good ↓ -47 ms (-2.6%) 1.10 s – 2.50 s n/a —
TTFB Time to First Byte 782 ms good ↓ -60 ms (-7.1%) 601 ms – 842 ms 1.95 s poor 40.3% 31.8% 28%

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 782 ms
element render delay 196 ms

LCP LAB Simulated vs LCP FIELD

Lab 977 ms
Field p75 2.28 s

The lab LCP is 0.43× the field p75 — real users likely have below-average hardware or network connectivity. A gap this wide usually means real users are on slower devices or networks than the simulated ones — the lab number is flattering you.

Page weight

Metric Value Change / range Trend
Page Weight 565 kB ↑ +119.2 kB (+27.5%) significant 443 kB – 565 kB
Requests 14 → no change 14 – 14
Third-party Weight 0 B → no change 0 B – 0 B
Third-party CPU 0 ms → no change 0 ms – 0 ms
Unused JS 0 B → no change 0 B – 0 B
Unused CSS 0 B → no change 0 B – 0 B

By resource type

Type Transfer Share Size Requests
media 87.6% 495 kB 2
image 5.3% 30.2 kB 2
font 3.9% 22.0 kB 1
stylesheet 1.4% 7.8 kB 1
document 1.2% 6.7 kB 1
other 0.6% 3.1 kB 1
Total 565 kB 14

Page health

Metric Value Change / range Trend
Main Thread Work 364 ms ↑ +57 ms (+18.6%) 273 ms – 885 ms
Long Tasks 1 ↑ +1 0 – 5
DOM Elements 86 → no change 86 – 86
Axe Violations Violating nodes from a full Axe CLI run (more than Lighthouse reports) 4 → no change 4 – 4
A11y Failures 3 → no change 3 – 3
A11y Failing Nodes 5 → no change 5 – 5

Main thread work

Task Time Share Duration Simulated
other 47% 172 ms
style layout 35% 128 ms
paint composite render 11% 42 ms
script evaluation 4% 14 ms
parse HTML 2% 8 ms
script parse compile 0% 1 ms
Total 364 ms

Axe violations axe-core 4.13.0, full rule set

4 violating nodes across 3 rules, 233 passing. This is a standalone Axe CLI run and is stricter than the subset Lighthouse already includes.

Accessibility failures 3 of 18 audits

  • color-contrast — Background and foreground colors do not have a sufficient contrast ratio. 2 nodes
  • target-size — Touch targets do not have sufficient size or spacing. 2 nodes
  • meta-viewport — `[user-scalable="no"]` is used in the `<meta name="viewport">` element or the `[maximum-scale]` attribute is less than 5. 1 node

Hygiene

HTTPS HSTS CSP Clickjacking protection Origin isolation Trusted Types bfcache http/1.1

Measurement log

Field history 25 weeks

Weekly p75 from the CrUX History API, backfilled in a single request.

Week ending LCPINPCLSFCPTTFB
2026-09-26 2.08 s 102 ms 0 2.07 s 1.84 s
2026-09-19 2.43 s 116 ms 0.010 2.33 s 1.28 s
2026-09-12 2.38 s 138 ms 0.010 2.33 s 1.27 s
2026-09-05 2.57 s 155 ms 0.010 2.57 s 1.20 s
2026-08-29 2.18 s 138 ms 0 2.18 s 1.31 s
2026-08-22 1.78 s 87 ms 0.050 1.78 s 1.11 s
2026-08-15 1.48 s 95 ms 0.160 1.48 s 763 ms
2026-08-08 1.39 s 93 ms 0.170 1.39 s 752 ms
2026-08-01 1.36 s 90 ms 0.160 1.36 s 734 ms
2026-07-25 1.35 s 90 ms 0.160 1.36 s 738 ms
2026-07-18 1.37 s 86 ms 0.160 1.36 s 770 ms
2026-07-11 1.51 s 102 ms 0.030 1.53 s 970 ms

Runs

Every stored run for this URL, newest first.

When Scores PerfLCPCLSTBTWeight RunsSpreadBenchTook Archive
Oct 5, 2026, 1:46 AM UTC 100 977 ms 0 0 ms 565 kB 3/3 ±2 2,675 +8% 26.8s Wayback
Sep 27, 2026, 11:49 PM UTC 100 979 ms 0 0 ms 443 kB 3/3 ±1 3,017 +21% 26s Wayback
Sep 20, 2026, 8:50 PM UTC 100 1.18 s 0 0 ms 536 kB 3/3 ±0 2,457 -1% 25.4s Wayback
Sep 13, 2026, 8:30 PM UTC 100 979 ms 0 0 ms 486 kB 3/3 ±2 2,484 0% 25.9s Wayback
Sep 6, 2026, 7:00 PM UTC 100 977 ms 0 0 ms 512 kB 3/3 ±2 2,372 -5% 25.8s Wayback
Aug 30, 2026, 6:04 PM UTC 98 2.17 s 0 0 ms 537 kB 3/3 ±2 2,359 -5% 26.6s Wayback
Aug 21, 2026, 9:35 AM UTC 99 982 ms 0 102 ms 493 kB 3/3 ±2 2,396 -4% 28.5s Wayback

Embed this score

Use this web component to show worldwideweb.cern.ch's scores on any website, updated whenever this instance re-measures. Don’t forget to bundle the speedlify2-score.js component code into your site! 

<speedlify2-score speedlify-url="https://www.speedlify.dev/" url="https://worldwideweb.cern.ch/"></speedlify2-score>