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.

Charts Compare Measurement runs Embed a score Open to Work

react.dev

https://react.dev/

79PERF 95A11Y 100BEST 92SEO ✗AXE ✓CWV

Ranks Overall #1,420 Developer Tooling #49 Frameworks and Libraries #9

Data from Oct 7, 2026, 10:56 PM UTC old, older than this category's 3 days freshness target Measured every 2 days · 19 runs since Aug 27, 2026

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

This data is old.

Sites are measured on a rolling schedule, so figures here are the newest successful measurement rather than a reading taken just now. Comparisons against other sites may span different points in time.

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

Stack

Next.js Built with Next.js
Uses ReactReact
Vercel Hosted by Vercel

Filmstrip LAB Throttled

How the page drew during the measured load, at 8 points across 3.59 s. Compare this filmstrip against another site.

  1. 449 ms
  2. 898 ms
  3. 1.35 s
  4. 1.80 s
  5. 2.24 s
  6. 2.69 s
  7. 3.14 s
  8. 3.59 s

Lighthouse Scores LAB Simulated

79
Performance
↓ -5 (-6%)
95
Accessibility
no change
100
Best Practices
no change
92
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 (2026-09-08 → 2026-10-05), url-level.

Metric Lab Simulated Field
Value Change / range Trend p75 Distribution
LCP CWV Largest Contentful Paint 4.30 s poor ↑ +393 ms (+10%) 2.73 s – 7.01 s 2.09 s good 81.1% 8.3% 10.7%
INP CWV Interaction to Next Paint — field only, no lab run can measure it n/a — 198 ms good 75.2% 15.2% 9.6%
CLS CWV Cumulative Layout Shift 0 good → no change 0 – 0 0 good 96% 1.7% 2.3%
TBT Total Blocking Time 288 ms needs work ↑ +51 ms (+21.5%) 132 ms – 386 ms n/a —
FCP First Contentful Paint 1.08 s good ↑ +18 ms (+1.7%) 1.06 s – 1.39 s 2.12 s needs work 67.8% 15.9% 16.3%
Speed Index 1.29 s good ↓ -151 ms (-10.4%) 1.29 s – 3.34 s n/a —
TTFB Time to First Byte 630 ms good ↑ +18 ms (+2.9%) 607 ms – 635 ms 739 ms good 77.4% 14.5% 8.1%

LCP Subparts LAB Throttled

The subparts attribute LCP to your server, resource discovery, download, or rendering. They come from one throttled load, the same one as the filmstrip, so they add up to that load’s LCP rather than the simulated Lab LCP above.

element render delay 1.91 s
time to first byte 589 ms

LCP LAB Simulated vs LCP FIELD

Lab 4.30 s
Field p75 2.09 s

The lab LCP is 2.06× the field p75 — real users likely have above-average hardware or network connectivity.

Page weight

Metric Value Change / range Trend
Page Weight 1.15 MB ↑ +252 B 1.15 MB – 1.15 MB
Requests 65 → no change 65 – 66
Third-party Weight 163 kB ↑ +145 B (+0.1%) 160 kB – 163 kB
Third-party CPU 29 ms ↓ -22 ms (-43%) significant 29 ms – 74 ms
Unused JS 224 kB ↑ +129 B (+0.1%) 221 kB – 224 kB
Unused CSS 16.2 kB → no change 16.2 kB – 16.2 kB

By resource type

Type Transfer Share Size Requests
script 49.5% 569 kB 13
font 28% 322 kB 9
image 15.3% 176 kB 34
document 3.8% 43.6 kB 1
stylesheet 1.8% 20.6 kB 1
other 1.6% 18.5 kB 7
Total 1.15 MB 65

Third parties 1 entities

Entity Transfer Size Main thread Simulated
Google Tag Manager script 163 kB 29 ms
Total 163 kB 29 ms

Without JavaScript

The same load, photographed twice at 412×823: once with scripts disabled, once as rendered.

Scripts disabled
As rendered

0% of pixels differ — they are identical. A shifted layout counts as difference, so a <noscript> banner alone can account for a large figure.

Page health

Metric Value Change / range Trend
Main Thread Work 1.72 s ↑ +85 ms (+5.2%) 1.32 s – 1.96 s
Long Tasks 8 → no change 7 – 11
DOM Elements 1,785 → no change 1,785 – 1,785
Axe Violations Violating nodes from a full Axe CLI run (more than Lighthouse reports) 6 → no change 6 – 6
A11y Failures 3 → no change 3 – 3
A11y Failing Nodes 5 → no change 5 – 5

Main thread work

Task Time Share Duration Simulated
script evaluation 56% 968 ms
other 17% 300 ms
style layout 12% 205 ms
script parse compile 10% 164 ms
parse HTML 3% 48 ms
paint composite render 2% 28 ms
garbage collection 1% 10 ms
Total 1.72 s

Axe violations axe-core 4.13.0, full rule set

6 violating nodes across 3 rules, 2183 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 3 nodes
    Offending elements
    1. .bg-gradient-left.dark\:bg-gradient-left-dark.border-primary\/10:nth-child(4) > .my-20.lg\:my-32.gap-2 > .max-w-7xl.mx-auto.flex-col > .lg\:ps-10.lg\:pe-5.w-full > .mb-2.lg\:my-16.lg\:bg-card > .lg\:bg-gray-10.lg\:dark\:bg-gray-70.dark\:shadow-inner-border-dark > .mt-0.lg\:-my-20.xs\:p-5 > .dark\:border-opacity-10.dark\:shadow-nav-dark.shadow-nav > .rounded-t-2xl.shadow-outer-border.backdrop-filter > .space-between.bg-gray-30\/20.text-center > .leading-snug.flex-row.justify-center > .text-gray-30 
      <span class="text-gray-30">example.com<!-- -->/</span>
    2. .border-primary\/5.dark\:border-primary-dark\/5.dark\:bg-gradient-right-dark:nth-child(5) > .my-20.lg\:my-32.gap-2 > .max-w-7xl.mx-auto.flex-col > .lg\:ps-10.lg\:pe-5.w-full > .mb-2.lg\:my-16.lg\:bg-card > .lg\:bg-gray-10.lg\:dark\:bg-gray-70.dark\:shadow-inner-border-dark > .mt-0.lg\:-my-20.xs\:p-5 > .dark\:border-opacity-10.dark\:shadow-nav-dark.shadow-nav > .rounded-t-2xl.shadow-outer-border.backdrop-filter > .space-between.bg-gray-30\/20.text-center > .leading-snug.flex-row.justify-center > .text-gray-30 
      <span class="text-gray-30">example.com<!-- -->/</span>
    3. .lg\:w-6\/12.relative.flex:nth-child(1) > .dark\:border-opacity-10.dark\:shadow-nav-dark.shadow-nav > .rounded-t-2xl.shadow-outer-border.backdrop-filter > .space-between.bg-gray-30\/20.text-center > .leading-snug.flex-row.justify-center > .text-gray-30 
      <span class="text-gray-30">example.com</span>
  • serious scrollable-region-focusable — Scrollable region must have keyboard access 2 nodes
    Offending elements
    1. .bg-gradient-left.dark\:bg-gradient-left-dark.border-primary\/10:nth-child(4) > .my-20.lg\:my-32.gap-2 > .max-w-7xl.mx-auto.flex-col > .lg\:ps-10.lg\:pe-5.w-full > .mb-2.lg\:my-16.lg\:bg-card > .lg\:bg-gray-10.lg\:dark\:bg-gray-70.dark\:shadow-inner-border-dark > .lg\:-m-5.dark\:bg-gray-95.dark\:shadow-nav-dark > .sandpack.sandpack--codeblock.overflow-x-auto > .sp-wrapper > .sp-stack > .sp-code-editor 
      <div class="sp-code-editor">
    2. .border-primary\/5.dark\:border-primary-dark\/5.dark\:bg-gradient-right-dark:nth-child(5) > .my-20.lg\:my-32.gap-2 > .max-w-7xl.mx-auto.flex-col > .lg\:ps-10.lg\:pe-5.w-full > .mb-2.lg\:my-16.lg\:bg-card > .lg\:bg-gray-10.lg\:dark\:bg-gray-70.dark\:shadow-inner-border-dark > .lg\:-m-5.dark\:bg-gray-95.dark\:shadow-nav-dark > .sandpack.sandpack--codeblock.overflow-x-auto > .sp-wrapper > .sp-stack > .sp-code-editor 
      <div class="sp-code-editor">
  • moderate heading-order — Heading levels should only increase by one 1 node
    Offending element
    1. .pb-16 > h4 
      <h4 class="leading-tight text-primary font-semibold text-3xl lg:text-4xl">Stay true to the web</h4>

Accessibility failures 3 of 26 audits

  • color-contrast — Background and foreground colors do not have a sufficient contrast ratio. 3 nodes
  • heading-order — Heading elements are not in a sequentially-descending order 1 node
  • label-content-name-mismatch — Elements with visible text labels do not have matching accessible names. 1 node

SEO failures 1 of 10 audits

  • crawlable-anchors — Links are not crawlable 8 items

Hygiene

HTTPS HSTS CSP Clickjacking protection Origin isolation Trusted Types bfcache h2

Measurement log

Field history 25 weeks

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

Week ending LCPINPCLSFCPTTFB
2026-10-03 2.08 s 201 ms 0 2.12 s 742 ms
2026-09-26 2.03 s 204 ms 0 2.07 s 745 ms
2026-09-19 2.02 s 204 ms 0 2.04 s 738 ms
2026-09-12 2.01 s 199 ms 0 2.04 s 748 ms
2026-09-05 2.00 s 194 ms 0 2.03 s 759 ms
2026-08-29 2.04 s 194 ms 0 2.07 s 767 ms
2026-08-22 2.08 s 193 ms 0 2.13 s 789 ms
2026-08-15 2.09 s 193 ms 0 2.14 s 793 ms
2026-08-08 2.16 s 195 ms 0 2.21 s 788 ms
2026-08-01 2.15 s 197 ms 0 2.20 s 790 ms
2026-07-25 2.09 s 199 ms 0 2.15 s 769 ms
2026-07-18 2.08 s 201 ms 0 2.14 s 761 ms

Runs

Every stored run for this URL, newest first.

When Scores PerfLCPCLSTBTWeight RunsSpreadBenchTook Archive
Oct 7, 2026, 10:56 PM UTC 79 4.30 s 0 288 ms 1.15 MB 3/3 ±10 2,473 -1% 65.4s Wayback
Oct 5, 2026, 6:11 PM UTC 84 3.91 s 0 237 ms 1.15 MB 3/3 ±2 2,488 0% 63.5s Wayback
Oct 1, 2026, 6:55 AM UTC 83 3.91 s 0 272 ms 1.15 MB 3/3 ±0 2,414 -3% 62.9s Wayback
Sep 29, 2026, 4:30 AM UTC 83 3.68 s 0 306 ms 1.15 MB 3/3 ±8 2,491 0% 64.3s Wayback
Sep 25, 2026, 4:57 PM UTC 73 5.30 s 0 325 ms 1.15 MB 3/3 ±16 2,504 +1% 64.2s Wayback
Sep 23, 2026, 11:01 AM UTC 94 2.73 s 0 157 ms 1.15 MB 3/3 ±3 3,445 +39% 58.9s Wayback
Sep 21, 2026, 7:50 AM UTC 82 3.91 s 0 284 ms 1.15 MB 3/3 ±4 2,476 0% 64.8s Wayback
Sep 18, 2026, 5:44 PM UTC 86 3.92 s 0 159 ms 1.15 MB 3/3 ±8 2,907 +17% 58.9s Wayback
Sep 16, 2026, 2:39 PM UTC 77 4.38 s 0 361 ms 1.15 MB 3/3 ±8 2,444 -2% 65.5s Wayback
Sep 14, 2026, 12:03 PM UTC 81 3.91 s 0 333 ms 1.15 MB 3/3 ±3 2,488 0% 65.8s Wayback
Sep 12, 2026, 6:59 AM UTC 70 7.01 s 0 268 ms 1.15 MB 3/3 ±13 2,358 -5% 65.5s Wayback
Sep 9, 2026, 10:59 PM UTC 84 3.92 s 0 231 ms 1.15 MB 3/3 ±20 2,269 -9% 36.5s Wayback
Sep 7, 2026, 10:33 PM UTC 73 5.25 s 0 319 ms 1.15 MB 3/3 ±6 2,468 -1% 34.8s Wayback
Sep 5, 2026, 8:04 PM UTC 80 4.37 s 0 263 ms 1.15 MB 3/3 ±6 2,654 +7% 33.3s Wayback
Sep 4, 2026, 6:13 PM UTC 81 4.07 s 0 295 ms 1.15 MB 3/3 ±7 2,323 -7% 35s Wayback
Sep 3, 2026, 6:56 AM UTC 79 3.91 s 0 386 ms 1.15 MB 3/3 ±3 2,452 -1% 35.4s Wayback
Sep 2, 2026, 3:06 AM UTC 82 3.92 s 0 274 ms 1.15 MB 3/3 ±4 2,492 0% 34.4s Wayback
Aug 31, 2026, 10:30 PM UTC 84 3.92 s 0 244 ms 1.15 MB 3/3 ±24 2,345 -6% 40.2s Wayback
Aug 27, 2026, 6:59 PM UTC 87 3.91 s 0 132 ms 1.15 MB 3/3 ±21 3,027 +22% 31.8s Wayback