londoncss.dev
Data from Aug 21, 2026, 1:47 PM UTC 2d old
Built Awesome #1,007 · 1 measurement · since Aug 21, 2026
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.
Scores
Lab metrics Lighthouse, mobile
| Metric | Current | Previous | Change | Best | Worst | Trend |
|---|---|---|---|---|---|---|
| LCP Largest Contentful Paint | 7.24 s | — | — | 7.24 s | 7.24 s | |
| CLS Cumulative Layout Shift | 0.001 | — | — | 0.001 | 0.001 | |
| TBT Total Blocking Time | 222 ms | — | — | 222 ms | 222 ms | |
| FCP First Contentful Paint | 4.99 s | — | — | 4.99 s | 4.99 s | |
| Speed Index | 4.99 s | — | — | 4.99 s | 4.99 s | |
| TTFB Time to First Byte | 698 ms | — | — | 698 ms | 698 ms |
What LCP is made of observed, unthrottled
A flat LCP number tells you something regressed. The subparts tell you whether it was the server, resource discovery, the download, or rendering.
Measured on the trace before throttling is modelled, so these are real durations that will not sum to the 7.24 s above — that figure is a simulation of the same load on a slow phone and connection. Read these for the proportions: which phase dominates.
Page weight
| Metric | Current | Previous | Change | Best | Worst | Trend |
|---|---|---|---|---|---|---|
| Page Weight | 882 kB | — | — | 882 kB | 882 kB | |
| Requests | 25 | — | — | 25 | 25 | |
| Third-party Weight | 840 kB | — | — | 840 kB | 840 kB | |
| Third-party CPU | 131 ms | — | — | 131 ms | 131 ms | |
| Unused JS | 284 kB | — | — | 284 kB | 284 kB | |
| Unused CSS | 203 kB | — | — | 203 kB | 203 kB |
By resource type
Third parties 3 entities
840 kB transferred, 131 ms of main thread time. This is the number most likely to regress without anyone on your team shipping anything.
Page health
| Metric | Current | Previous | Change | Best | Worst | Trend |
|---|---|---|---|---|---|---|
| Main Thread Work | 1.48 s | — | — | 1.48 s | 1.48 s | |
| Long Tasks | 7 | — | — | 7 | 7 | |
| DOM Elements | 649 | — | — | 649 | 649 | |
| Axe Violations Violating nodes from a full axe run — stricter than Lighthouse's subset | 35 | — | — | 35 | 35 | |
| A11y Failures | 0 | — | — | 0 | 0 | |
| A11y Failing Nodes | 0 | — | — | 0 | 0 |
Main thread work
Axe violations axe-core 4.13.0, full rule set
35 violating nodes across 5 rules, 659 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.
-
moderate
region— All page content should be contained by landmarks 30 nodes -
moderate
landmark-unique— Landmarks should have a unique role or role/label/title (i.e. accessible name) combination 2 nodes -
critical
aria-allowed-attr— Elements must only use supported ARIA attributes 1 node -
moderate
landmark-no-duplicate-banner— Document should not have more than one banner landmark 1 node -
moderate
landmark-no-duplicate-contentinfo— Document should not have more than one contentinfo landmark 1 node
Hygiene
Changes rarely — which is exactly why a change is worth noticing.
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 | Perf | LCP | CLS | TBT | Weight | Runs | Spread | Bench | Took |
|---|---|---|---|---|---|---|---|---|---|
| Aug 21, 2026, 1:47 PM UTC | 60 | 7.24 s | 0.001 | 222 ms | 882 kB | 3/3 | ±6 | 2,482 | 29s |
Embed this score
Live below, then the markup that produces it. Drop that on any page to show
londoncss.dev's scores, updated whenever this instance
re-measures — more about the component. Don’t forget to bundle the speedlify2-score.js component code into your site!
<speedlify2-score speedlify-url="https://www.speedlify.dev/" url="https://www.londoncss.dev/"></speedlify2-score>