colorjs.io

Ranks Overall #1,593 Built Awesome #1,055

Data from Oct 3, 2026, 7:40 AM UTC 5d old Measured once a week · 7 runs since Aug 20, 2026

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

The measuring machine was faster than most in this project.

Lighthouse benchmark index was 4,338, 75% faster than this project's median of 2,486. CPU-bound metrics — TBT, TTI, main thread work — are affected by this and may have moved without the site changing at all.

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

Stack

Hosted by Netlify

Lighthouse Scores LAB Simulated

Performance

↑ +9 (+10.6%)

Accessibility

no change

100

Best Practices

no change

SEO

no change

Metrics LAB

No field data: the Chrome UX Report is not being collected for this project, so every figure below is from the Lighthouse run.

Metric	Lab Simulated
LCP CWV (estimate) Largest Contentful Paint	2.60 s needs work	↓ -857 ms (-24.8%) 1.87 s – 4.67 s
INP CWV Interaction to Next Paint — field only, no lab run can measure it	n/a	—
CLS CWV (estimate) Cumulative Layout Shift	0.055 good	→ no change 0.046 – 0.086
TBT Total Blocking Time	5 ms good	↓ -22 ms (-81.5%) 5 ms – 70 ms
FCP First Contentful Paint	2.04 s needs work	↓ -985 ms (-32.6%) 1.71 s – 3.60 s
Speed Index	2.16 s good	↓ -864 ms (-28.6%) 1.71 s – 5.08 s
TTFB Time to First Byte	606 ms good	↑ +1 ms (+0.2%) 605 ms – 671 ms

Metric

Lab Simulated

Value

Change / range

Trend

LCP CWV (estimate) Largest Contentful Paint

2.60 s needs work

↓ -857 ms (-24.8%) 1.87 s – 4.67 s

INP CWV Interaction to Next Paint — field only, no lab run can measure it

n/a

—

CLS CWV (estimate) Cumulative Layout Shift

0.055 good

→ no change 0.046 – 0.086

TBT Total Blocking Time

5 ms good

↓ -22 ms (-81.5%) 5 ms – 70 ms

FCP First Contentful Paint

2.04 s needs work

↓ -985 ms (-32.6%) 1.71 s – 3.60 s

Speed Index

2.16 s good

↓ -864 ms (-28.6%) 1.71 s – 5.08 s

TTFB Time to First Byte

606 ms good

↑ +1 ms (+0.2%) 605 ms – 671 ms

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.

element render delay 207 ms

time to first byte 110 ms

Page weight

Metric	Value	Change / range
Page Weight	384 kB	↑ +517 B (+0.1%) 382 kB – 385 kB
Requests	161	→ no change 161 – 161
Third-party Weight	221 kB	↑ +2.0 kB (+0.9%) 219 kB – 222 kB
Third-party CPU	0 ms	↓ -0 ms (-66.7%) 0 ms – 0 ms
Unused JS	42.6 kB	→ no change 42.6 kB – 42.6 kB
Unused CSS	0 B	→ no change 0 B – 0 B

Metric

Value

Change / range

Trend

Page Weight

384 kB

↑ +517 B (+0.1%) 382 kB – 385 kB

Requests

161

→ no change 161 – 161

Third-party Weight

221 kB

↑ +2.0 kB (+0.9%) 219 kB – 222 kB

Third-party CPU

0 ms

↓ -0 ms (-66.7%) 0 ms – 0 ms

Unused JS

42.6 kB

→ no change 42.6 kB – 42.6 kB

Unused CSS

0 B

→ no change 0 B – 0 B

By resource type

Type	Share	Size	Requests
script	62.1%	238 kB	140
font	27.1%	104 kB	3
image	6.9%	26.3 kB	8
stylesheet	2.4%	9.3 kB	8
document	1.5%	5.6 kB	1
other	<0.1%	72 B	1
Total		384 kB	161

Third parties 7 entities

Entity	Transfer	Size	Main thread Simulated
Google Fonts	font	106 kB	0 ms
JSDelivr CDN	script	70.1 kB	0 ms
blissfuljs.com		14.2 kB	0 ms
opencollective.com		12.9 kB	0 ms
prismjs.com		10.5 kB	0 ms
All 7		221 kB	0 ms

Entity

Transfer

Size

Main thread Simulated

Google Fonts

font

106 kB

0 ms

JSDelivr CDN

script

70.1 kB

0 ms

blissfuljs.com

14.2 kB

0 ms

opencollective.com

12.9 kB

0 ms

prismjs.com

10.5 kB

0 ms

All 7

221 kB

0 ms

Page health

Metric	Value	Change / range
Main Thread Work	2.52 s	↓ -506 ms (-16.7%) 2.05 s – 3.03 s
Long Tasks	2	↓ -1 (-33.3%) 2 – 3
DOM Elements	908	→ no change 908 – 908
Axe Violations Violating nodes from a full Axe CLI run (more than Lighthouse reports)	40	→ no change 27 – 40
A11y Failures	5	→ no change 5 – 5
A11y Failing Nodes	28	→ no change 28 – 28

Metric

Value

Change / range

Trend

Main Thread Work

2.52 s

↓ -506 ms (-16.7%) 2.05 s – 3.03 s

Long Tasks

↓ -1 (-33.3%) 2 – 3

DOM Elements

908

→ no change 908 – 908

Axe Violations Violating nodes from a full Axe CLI run (more than Lighthouse reports)

→ no change 27 – 40

A11y Failures

→ no change 5 – 5

A11y Failing Nodes

→ no change 28 – 28

Main thread work

Task	Share	Duration Simulated
other	38%	962 ms
paint composite render	33%	824 ms
style layout	24%	603 ms
script evaluation	4%	94 ms
parse HTML	1%	22 ms
script parse compile	0%	11 ms
garbage collection	0%	7 ms
Total		2.52 s

Task

Time

Duration Simulated

other

38%

962 ms

paint composite render

33%

824 ms

style layout

24%

603 ms

script evaluation

94 ms

parse HTML

22 ms

script parse compile

11 ms

garbage collection

7 ms

Total

2.52 s

Axe violations axe-core 4.13.0, full rule set

40 violating nodes across 7 rules, 1164 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 24 nodes

Offending elements (5 of 24)

section:nth-child(2) > ul > li:nth-child(3) > a

<a href="https://limonte.dev/total-npm-downloads/?package=colorjs.io">309 million total npm downloads</a>

section:nth-child(2) > ul > li:nth-child(4) > a:nth-child(1)

<a href="https://www.npmjs.com/browse/depended/colorjs.io">high impact projects</a>

a[href$="sass-lang.com/"]

<a href="https://sass-lang.com/">Sass</a>

a[href$="open-props.style/"]

<a href="https://open-props.style/">Open Props</a>

a[href$="axe/"]

<a href="https://www.deque.com/axe/">axe</a>

serious scrollable-region-focusable — Scrollable region must have keyboard access 11 nodes
Offending elements (5 of 11)
1. pre:nth-child(10)
```
<pre class=" language-js">
```
2. .cn-ignore > .language-html
```
<pre class=" language-html">
```
3. section:nth-child(4) > pre:nth-child(3)
```
<pre class=" language-js">
```
4. section:nth-child(4) > pre:nth-child(5)
```
<pre class=" language-js">
```
5. section:nth-child(5) > pre:nth-child(3)
```
<pre class=" language-js">
```
moderate heading-order — Heading levels should only increase by one 1 node
Offending element
1. article:nth-child(1) > h4
```
<h4>Fully color space aware</h4>
```
serious html-has-lang — <html> element must have a lang attribute 1 node
Offending element
1. html
```
<html data-route="/">
```
critical image-alt — Images must have alternative text 1 node
Offending element
1. img[width="300"]
```
<img src="https://opencollective.com/color/donate/button@2x.png?color=blue" width="300">
```
moderate landmark-unique — Landmarks should have a unique role or role/label/title (i.e. accessible name) combination 1 node
Offending element
1. header > nav
```
<nav>
```

serious link-name — Links must have discernible text 1 node

Offending element

section:nth-child(10) > a[target="_blank"]

<a href="https://opencollective.com/color/donate" target="_blank"> <img src="https://opencollective.com/color/donate/button@2x.png?color=blue" width="300"> </a>

Accessibility failures 5 of 18 audits

color-contrast — Background and foreground colors do not have a sufficient contrast ratio. 24 nodes
heading-order — Heading elements are not in a sequentially-descending order 1 node
html-has-lang — `<html>` element does not have a `[lang]` attribute 1 node
image-alt — Image elements do not have `[alt]` attributes 1 node
link-name — Links do not have a discernible name 1 node

SEO failures 3 of 8 audits

meta-description — Document does not have a meta description
link-text — Links do not have descriptive text 2 items
image-alt — Image elements do not have `[alt]` attributes 1 item

Hygiene

HTTPS HSTS CSP Clickjacking protection Origin isolation Trusted Types bfcache h2

Measurement log

Every stored run for this URL, newest first.

When	Perf	LCP	CLS	TBT	Weight	Runs	Spread	Bench	Took	Archive
Oct 3, 2026, 7:40 AM UTC	94	2.60 s	0.055	5 ms	384 kB	3/3	±1	4,338 +74%	27.9s	Wayback
Sep 25, 2026, 11:53 PM UTC	85	3.46 s	0.055	27 ms	383 kB	3/3	±14	2,484 0%	36s	Wayback
Sep 18, 2026, 8:30 PM UTC	98	1.87 s	0.055	29 ms	382 kB	3/3	±23	2,260 -9%	35.6s	Wayback
Sep 11, 2026, 5:36 PM UTC	82	3.78 s	0.055	24 ms	383 kB	3/3	±17	2,453 -1%	37.4s	Wayback
Sep 4, 2026, 2:52 PM UTC	71	4.67 s	0.086	70 ms	385 kB	2/3	±19	2,502 +1%	33.3s	Wayback
Aug 28, 2026, 1:51 PM UTC	86	3.32 s	0.055	26 ms	382 kB	3/3	±1	2,380 -4%	33.8s	Wayback
Aug 20, 2026, 4:40 PM UTC	93	2.79 s	0.046	11 ms	384 kB	3/3	±24	3,329 +34%	33.2s	Wayback

When

Scores

Perf

LCP

CLS

TBT

Weight

Runs

Spread

Bench

Took

Embed this score

Use this web component to show colorjs.io'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://colorjs.io/"></speedlify2-score>

Stack

Lighthouse Scores LAB 🤖 Simulated

Metrics LAB

LCP Subparts LAB 🐇 Unthrottled

Page weight

By resource type

Third parties 7 entities

Page health

Main thread work

Axe violations axe-core 4.13.0, full rule set

Accessibility failures 5 of 18 audits

SEO failures 3 of 8 audits

Hygiene

Measurement log

Embed this score

Lighthouse Scores LAB Simulated

LCP Subparts LAB Unthrottled