speedlify2

Lighthouse lab metrics, Axe, and Chrome UX Report field data for a list of sites recorded and compared over time.

Charts Compare Measurement runs Embed a score

worldwideweb.cern.ch

https://worldwideweb.cern.ch/

100 80 100 100 !AXE !CWV

Ranks Overall #992 Built Awesome #770

Data from Sep 6, 2026, 7:00 PM UTC old Measured once a week · 3 runs since Aug 21, 2026

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

Lighthouse Scores

100
Performance
↑ +2 (+2%)
80
Accessibility
no change
100
Best Practices
no change
100
SEO
no change

Metrics Lighthouse, mobile Chrome UX Report

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

Field figures are the p75 across real Chrome users over a 28-day trailing window (2026-08-08 → 2026-09-04), origin-level.

Metric Lab Lighthouse Field Chrome UX Report
Value Change / range Trend p75 Distribution
LCP CWV Largest Contentful Paint 977 ms good ↓ -1190 ms (-54.9%) 977 ms – 2.17 s 2.57 s needs work 73.2% 17.3% 9.5%
INP CWV Interaction to Next Paint — field only, no lab run can measure it n/a — 138 ms good 83.5% 10.7% 5.8%
CLS CWV Cumulative Layout Shift 0 good → no change 0 – 0 0.010 good 93.2% 5.2% 1.7%
TBT Total Blocking Time 0 ms good → no change 0 ms – 102 ms n/a —
FCP First Contentful Paint 902 ms good ↓ -665 ms (-42.4%) 902 ms – 1.57 s 2.52 s needs work 54.3% 30% 15.7%
Speed Index 1.45 s good ↓ -1055 ms (-42.1%) 1.45 s – 2.50 s n/a —
TTFB Time to First Byte 601 ms good ↓ -121 ms (-16.8%) 601 ms – 722 ms 1.20 s needs work 60.4% 30.3% 9.3%

LCP Subparts lab observed, unthrottled

The subparts attribute LCP to your server, resource discovery, download, or rendering. Note that the Lab LCP shown above is throttled.

time to first byte 600 ms
element render delay 155 ms

Lab LCP vs Field LCP Chrome UX Report

Lab 977 ms
Field p75 2.57 s

The lab LCP is 0.38× 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 512 kB ↓ -24.4 kB (-4.7%) 493 kB – 537 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

  • media 86.3% 442 kB · 2 req
  • image 5.9% 30.2 kB · 2 req
  • font 4.3% 22.0 kB · 1 req
  • stylesheet 1.5% 7.8 kB · 1 req
  • document 1.3% 6.7 kB · 1 req
  • other 0.6% 3.1 kB · 1 req

Page health

Metric Value Change / range Trend
Main Thread Work 317 ms ↑ +44 ms (+16.2%) 273 ms – 885 ms
Long Tasks 0 → no change 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

other 153 ms
style layout 109 ms
paint composite render 34 ms
script evaluation 12 ms
parse HTML 10 ms
script parse compile 1 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.

  • serious color-contrast — Elements must meet minimum color contrast ratio thresholds 2 nodes
  • moderate landmark-unique — Landmarks should have a unique role or role/label/title (i.e. accessible name) combination 1 node
  • moderate meta-viewport — Zooming and scaling must not be disabled 1 node

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
2026-09-05 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
2026-07-04 2.35 s 107 ms 0 2.14 s 1.38 s
2026-06-27 1.61 s 87 ms 0 1.61 s 1.16 s
2026-06-20 1.36 s 82 ms 0.020 1.34 s 800 ms

Runs

Every stored run for this URL, newest first.

When Scores PerfLCPCLSTBTWeight RunsSpreadBenchTook Archive
Sep 6, 2026, 7:00 PM UTC 100 977 ms 0 0 ms 512 kB 3/3 ±2 2,372 -4% 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 -3% 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>