speedlify2

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

Measurement runs · Embed a score · Field data from the Chrome UX Report ·

heroku.com

https://www.heroku.com/

76 93 58 92 ✓CWV 4AXE

Data from Aug 21, 2026, 10:39 AM UTC — 8h old.

Web Hosts · 1 measurement · since Aug 21, 2026 · last attempt 8h

Stack

Detected on the same page load as the accessibility pass — the generator from <meta name="generator"> or the shape of the page, the host from response headers.

Self-hosted · nginx Hosted by Self-hosted

Core Web Vitals field data, url-level

Real Chrome users, 28-day window (2026-07-23 → 2026-08-19). This is what Google measures you on.

LCP 1.52 s good
INP 146 ms good
CLS 0 good

Scores

76
Performance
no change
93
Accessibility
no change
58
Best Practices
no change
92
SEO
no change

Lab metrics Lighthouse, mobile

Metric Current Previous Change Best Worst Trend
LCP Largest Contentful Paint 2.94 s — — 2.94 s 2.94 s
CLS Cumulative Layout Shift 0.017 — — 0.017 0.017
TBT Total Blocking Time 628 ms — — 628 ms 628 ms
FCP First Contentful Paint 2.32 s — — 2.32 s 2.32 s
Speed Index 2.87 s — — 2.87 s 2.87 s
TTFB Time to First Byte 611 ms — — 611 ms 611 ms

What LCP is made of

A flat LCP number tells you something regressed. The subparts tell you whether it was the server, resource discovery, the download, or rendering.

element render delay 183 ms
time to first byte 11 ms

Field data Chrome UX Report, url-level

Real Chrome users, 28-day trailing window (2026-07-23 → 2026-08-19). This is what Google measures you on.

Metric p75 Rating Distribution (good / needs work / poor)
LCP CWV 1.52 s good 90.6% good
INP CWV Interaction to Next Paint — field only, Lighthouse cannot measure this in a lab run 146 ms good 86.1% good
CLS CWV 0 good 96.9% good
FCP 1.33 s good 85.6% good
TTFB 623 ms good 82.3% good

Lab vs field

Lab LCP 2.94 s · field p75 1.52 s · real users are 0.52× faster than the lab.

Field history 25 weeks

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

Week ending LCPINPCLSFCPTTFB
2026-08-15 1.52 s 146 ms 0 1.33 s 627 ms
2026-08-08 1.45 s 148 ms 0 1.29 s 616 ms
2026-08-01 1.54 s 147 ms 0 1.35 s 657 ms
2026-07-25 1.53 s 148 ms 0 1.35 s 664 ms
2026-07-18 1.51 s 148 ms 0 1.33 s 671 ms
2026-07-11 1.66 s 150 ms 0 1.42 s 726 ms
2026-07-04 1.55 s 154 ms 0 1.36 s 695 ms
2026-06-27 1.55 s 155 ms 0 1.37 s 700 ms
2026-06-20 1.53 s 155 ms 0 1.35 s 698 ms
2026-06-13 1.45 s 154 ms 0 1.28 s 660 ms
2026-06-06 1.47 s 152 ms 0 1.29 s 665 ms
2026-05-30 1.47 s 152 ms 0 1.29 s 656 ms

Page weight

Metric Current Previous Change Best Worst Trend
Page Weight 2.65 MB — — 2.65 MB 2.65 MB
Requests 106 — — 106 106
Third-party Weight 1.06 MB — — 1.06 MB 1.06 MB
Third-party CPU 283 ms — — 283 ms 283 ms
Unused JS 736.7 kB — — 736.7 kB 736.7 kB
Unused CSS 97.7 kB — — 97.7 kB 97.7 kB

By resource type

script 1.70 MB · 49 req
other 465.8 kB · 15 req
font 212.0 kB · 6 req
stylesheet 130.2 kB · 7 req
document 79.8 kB · 2 req
image 62.0 kB · 25 req
third party 1.16 MB · 29 req

Third parties 10 entities

1.06 MB transferred, 283 ms of main thread time. This is the number most likely to regress without anyone on your team shipping anything.

Google Tag Manager 511.7 kB · 168 ms CPU
Google CDN 320.2 kB · 84 ms CPU
herokucdn.com 146.2 kB · 0 ms CPU
LinkedIn Ads 41.1 kB · 10 ms CPU
Parse.ly 22.9 kB · 17 ms CPU

Page health

Metric Current Previous Change Best Worst Trend
Main Thread Work 4.15 s — — 4.15 s 4.15 s
Long Tasks 19 — — 19 19
DOM Elements 2,312 — — 2,312 2,312
Axe Violations Violating nodes from a full axe run — stricter than Lighthouse's subset 4 — — 4 4
A11y Failures 2 — — 2 2
A11y Failing Nodes 12 — — 12 12

Main thread work

script evaluation 2.22 s
other 785 ms
style layout 473 ms
script parse compile 337 ms
parse HTML 163 ms
paint composite render 126 ms
garbage collection 44 ms

Axe violations axe-core 4.13.0, full rule set

4 violating nodes across 3 rules, 1558 passing. This is a standalone axe run, stricter than the subset Lighthouse folds into its score above — and it is the second tiebreaker in the ranking.

  • 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 region — All page content should be contained by landmarks 1 node

Accessibility failures 2 of 29 audits

Tracked as a count, not just the score — the weighted score is coarse enough that you can ship a broken component and barely move it.

  • target-size — Touch targets do not have sufficient size or spacing. 10 nodes
  • color-contrast — Background and foreground colors do not have a sufficient contrast ratio. 2 nodes

Hygiene

Changes rarely — which is exactly why a change is worth noticing.

HTTPS HSTS CSP Clickjacking protection Origin isolation Trusted Types bfcache h2

Measurement log

Every stored run for this URL, newest first. Failures are kept as records — "this site was down on Tuesday" is data too.

When PerfLCPCLSTBTWeight RunsSpreadBenchTook
Aug 21, 2026, 10:39 AM UTC 76 2.94 s 0.017 628 ms 2.65 MB 3/3 ±2 2,918 38.7s

Embed this score

Live below, then the markup that produces it. Drop that on any page to show heroku.com's scores, updated whenever this instance re-measures — more about the component. Don’t forget to bundle the speedlify-score.js component code into your site! 

<speedlify-score speedlify-url="https://zachleat.github.io/speedlify2/" url="https://www.heroku.com/"></speedlify-score>