emberjs.com

Ranks Overall #1,439 Developer Tooling #52 Frameworks and Libraries #10

Data from Oct 7, 2026, 10:53 PM UTC 4d 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 4d 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

Built with Ember.js

Hosted by Netlify

Filmstrip LAB Throttled

How the page drew during the measured load, at 8 points across 3.42 s. Compare this filmstrip against another site.

427 ms
854 ms
1.28 s
1.71 s
2.13 s
2.56 s
2.99 s
3.42 s

Lighthouse Scores LAB Simulated

Performance

↑ +3 (+4.3%)

Accessibility

no change

Best Practices

no change

100

SEO

no change

Metrics LAB FIELD

Core Web Vitals: passing 2 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
LCP CWV Largest Contentful Paint	4.22 s poor	↓ -1014 ms (-19.4%) 4.02 s – 8.12 s	2.21 s good	80.9% 12.6% 6.6%
INP CWV Interaction to Next Paint — field only, no lab run can measure it	n/a	—	—	—
CLS CWV Cumulative Layout Shift	0 good	→ no change 0 – 0	0 good	96.7% 2.6% 0.7%
TBT Total Blocking Time	550 ms needs work	↑ +75 ms (+15.8%) 179 ms – 550 ms	n/a	—
FCP First Contentful Paint	1.09 s good	↑ +31 ms (+2.9%) 1.05 s – 1.28 s	1.99 s needs work	69% 20.2% 10.8%
Speed Index	1.09 s good	↑ +31 ms (+2.9%) 1.05 s – 4.31 s	n/a	—
TTFB Time to First Byte	638 ms good	↑ +31 ms (+5.1%) significant 604 ms – 826 ms	708 ms good	79% 16.6% 4.4%

Metric

Lab Simulated

Field

Value

Change / range

Trend

p75

Distribution

LCP CWV Largest Contentful Paint

4.22 s poor

↓ -1014 ms (-19.4%) 4.02 s – 8.12 s

2.21 s good

80.9% 12.6% 6.6%

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

n/a

—

CLS CWV Cumulative Layout Shift

0 good

→ no change 0 – 0

0 good

96.7% 2.6% 0.7%

TBT Total Blocking Time

550 ms needs work

↑ +75 ms (+15.8%) 179 ms – 550 ms

n/a

—

FCP First Contentful Paint

1.09 s good

↑ +31 ms (+2.9%) 1.05 s – 1.28 s

1.99 s needs work

69% 20.2% 10.8%

Speed Index

1.09 s good

↑ +31 ms (+2.9%) 1.05 s – 4.31 s

n/a

—

TTFB Time to First Byte

638 ms good

↑ +31 ms (+5.1%) significant 604 ms – 826 ms

708 ms good

79% 16.6% 4.4%

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.

resource load delay 1.33 s

resource load duration 679 ms

time to first byte 591 ms

element render delay 18 ms

LCP LAB Simulated vs LCP FIELD

Lab 4.22 s

Field p75 2.21 s

The lab LCP is 1.9× the field p75 — real users likely have above-average hardware or network connectivity.

Page weight

Metric	Value	Change / range
Page Weight	1.16 MB	↓ -48 B 1.16 MB – 1.20 MB
Requests	48	→ no change 34 – 49
Third-party Weight	186 kB	↑ +171 B (+0.1%) 180 kB – 186 kB
Third-party CPU	59 ms	↑ +4 ms (+6.6%) 41 ms – 61 ms
Unused JS	322 kB	↓ -84 B 319 kB – 344 kB
Unused CSS	0 B	→ no change 0 B – 0 B

Metric

Value

Change / range

Trend

Page Weight

1.16 MB

↓ -48 B 1.16 MB – 1.20 MB

Requests

→ no change 34 – 49

Third-party Weight

186 kB

↑ +171 B (+0.1%) 180 kB – 186 kB

Third-party CPU

59 ms

↑ +4 ms (+6.6%) 41 ms – 61 ms

Unused JS

322 kB

↓ -84 B 319 kB – 344 kB

Unused CSS

0 B

→ no change 0 B – 0 B

By resource type

Type	Share	Size	Requests
script	47.5%	550 kB	7
image	28.7%	333 kB	15
font	19.4%	225 kB	1
document	2.4%	27.7 kB	1
stylesheet	1.9%	21.8 kB	19
other	0.1%	1.4 kB	3
Total		1.16 MB	48

Third parties 2 entities

Entity	Transfer	Size	Main thread Simulated
Google Tag Manager	script	164 kB	43 ms
Google Analytics		21.6 kB	16 ms
Total		186 kB	59 ms

Entity

Transfer

Size

Main thread Simulated

Google Tag Manager

script

164 kB

43 ms

Google Analytics

21.6 kB

16 ms

Total

186 kB

59 ms

Without JavaScript

The same load, photographed twice at 412×823: once with scripts disabled, once 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
Main Thread Work	1.78 s	↑ +198 ms (+12.5%) 1.17 s – 6.01 s
Long Tasks	6	→ no change 4 – 7
DOM Elements	523	↓ -1 (-0.2%) 523 – 529
Axe Violations Violating nodes from a full Axe CLI run (more than Lighthouse reports)	6	→ no change 6 – 6
A11y Failures	2	→ no change 2 – 2
A11y Failing Nodes	6	→ no change 6 – 6

Metric

Value

Change / range

Trend

Main Thread Work

1.78 s

↑ +198 ms (+12.5%) 1.17 s – 6.01 s

Long Tasks

→ no change 4 – 7

DOM Elements

523

↓ -1 (-0.2%) 523 – 529

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

→ no change 6 – 6

A11y Failures

→ no change 2 – 2

A11y Failing Nodes

→ no change 6 – 6

Main thread work

Task	Share	Duration Simulated
script evaluation	40%	711 ms
other	24%	434 ms
style layout	17%	309 ms
script parse compile	11%	196 ms
paint composite render	5%	86 ms
parse HTML	3%	48 ms
Total		1.78 s

Task

Time

Duration Simulated

script evaluation

40%

711 ms

other

24%

434 ms

style layout

17%

309 ms

script parse compile

11%

196 ms

paint composite render

86 ms

parse HTML

48 ms

Total

1.78 s

Axe violations axe-core 4.13.0, full rule set

6 violating nodes across 2 rules, 939 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. #ember-addons-panel-0 > code > pre
```
<pre class="mt-3">&gt; ember install ember-concurrency</pre>
```
2. .bg-shape-boxes > .container > .grid.lg\:grid-2.list-unstyled > .card--link.card:nth-child(1) > .card__content > h3 > a
```
<a href="https://guides.emberjs.com/release/">Read the Guides</a>
```
3. h3 > a[href$="blog.emberjs.com"]
```
<a href="https://blog.emberjs.com">Read Our Blog</a>
```
serious link-in-text-block — Links must be distinguishable without relying on color 3 nodes
Offending elements
1. .footer-help > .py-1.container > a:nth-child(1)
```
<a href="mailto:help@emberjs.com?subject=Help">email</a>
```
2. .py-1.container > a:nth-child(2)
```
<a href="https://github.com/ember-learn/ember-website/issues/new"> issue</a>
```
3. .py-1.container > a[href$="emberjs"]
```
<a href="https://discord.gg/emberjs">Ember Discord</a>
```

Accessibility failures 2 of 27 audits

color-contrast — Background and foreground colors do not have a sufficient contrast ratio. 3 nodes
link-in-text-block — Links rely on color to be distinguishable. 3 nodes

Best Practices failures 2 of 20 audits

errors-in-console — Browser errors were logged to the console 1 item
valid-source-maps — Missing source maps for large first-party JavaScript 2 items

Hygiene

HTTPS HSTS CSP Clickjacking protection Origin isolation Trusted Types bfcache h2 1 console error

Measurement log

Field history 25 weeks

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

Week ending	LCP	INP	FCP	TTFB
2026-10-03	2.21 s	—	1.98 s	725 ms
2026-09-26	2.15 s	95 ms	1.87 s	750 ms
2026-09-19	2.08 s	98 ms	1.83 s	783 ms
2026-09-12	2.03 s	113 ms	1.83 s	827 ms
2026-09-05	1.92 s	109 ms	1.66 s	799 ms
2026-08-29	1.84 s	116 ms	1.67 s	842 ms
2026-08-22	1.91 s	114 ms	1.59 s	853 ms
2026-08-15	1.91 s	113 ms	1.57 s	853 ms
2026-08-08	1.91 s	121 ms	1.59 s	857 ms
2026-08-01	1.84 s	106 ms	1.50 s	769 ms
2026-07-25	1.75 s	99 ms	1.48 s	666 ms
2026-07-18	1.63 s	99 ms	1.46 s	627 ms

Week ending

LCP

INP

CLS

FCP

TTFB

2026-10-03

2.21 s

—

1.98 s

725 ms

2026-09-26

2.15 s

95 ms

1.87 s

750 ms

2026-09-19

2.08 s

98 ms

1.83 s

783 ms

2026-09-12

2.03 s

113 ms

1.83 s

827 ms

2026-09-05

1.92 s

109 ms

1.66 s

799 ms

2026-08-29

1.84 s

116 ms

1.67 s

842 ms

2026-08-22

1.91 s

114 ms

1.59 s

853 ms

2026-08-15

1.91 s

113 ms

1.57 s

853 ms

2026-08-08

1.91 s

121 ms

1.59 s

857 ms

2026-08-01

1.84 s

106 ms

1.50 s

769 ms

2026-07-25

1.75 s

99 ms

1.48 s

666 ms

2026-07-18

1.63 s

99 ms

1.46 s

627 ms

Runs

Every stored run for this URL, newest first.

When	Perf	LCP	TBT	Weight	Runs	Spread	Bench	Took	Archive
Oct 7, 2026, 10:53 PM UTC	72	4.22 s	550 ms	1.16 MB	3/3	±6	2,427 -2%	57s	Wayback
Oct 5, 2026, 6:08 PM UTC	69	5.23 s	475 ms	1.16 MB	3/3	±3	2,502 +1%	53.4s	Wayback
Oct 1, 2026, 6:52 AM UTC	67	5.83 s	462 ms	1.16 MB	3/3	±4	2,316 -7%	53.4s	Wayback
Sep 29, 2026, 4:27 AM UTC	67	7.55 s	302 ms	1.16 MB	3/3	±8	2,482 0%	58.4s	Wayback
Sep 25, 2026, 4:54 PM UTC	67	5.30 s	523 ms	1.16 MB	3/3	±1	2,494 0%	54.5s	Wayback
Sep 23, 2026, 10:58 AM UTC	72	7.25 s	179 ms	1.16 MB	3/3	±8	3,378 +36%	51.8s	Wayback
Sep 21, 2026, 7:47 AM UTC	73	4.28 s	512 ms	1.16 MB	3/3	±11	2,489 0%	54.8s	Wayback
Sep 18, 2026, 5:41 PM UTC	73	5.44 s	320 ms	1.16 MB	3/3	±8	3,031 +22%	53.2s	Wayback
Sep 16, 2026, 9:22 AM UTC	68	5.25 s	497 ms	1.16 MB	3/3	±2	2,430 -2%	55.4s	Wayback
Sep 14, 2026, 6:02 AM UTC	72	5.45 s	323 ms	1.16 MB	3/3	±8	3,360 +35%	53.4s	Wayback
Sep 11, 2026, 11:34 PM UTC	75	4.19 s	436 ms	1.16 MB	3/3	±7	2,382 -4%	56.7s	Wayback
Sep 9, 2026, 10:57 PM UTC	75	4.21 s	458 ms	1.16 MB	3/3	±15	2,246 -10%	33.7s	Wayback
Sep 7, 2026, 10:31 PM UTC	70	5.88 s	367 ms	1.19 MB	3/3	±17	2,509 +1%	33.4s	Wayback
Sep 5, 2026, 8:02 PM UTC	67	6.26 s	434 ms	1.20 MB	3/3	±7	2,624 +6%	29s	Wayback
Sep 4, 2026, 11:02 AM UTC	66	6.22 s	473 ms	1.20 MB	3/3	±5	2,497 0%	27.1s	Wayback
Sep 3, 2026, 6:54 AM UTC	75	4.02 s	482 ms	1.20 MB	3/3	±14	2,475 0%	28s	Wayback
Sep 2, 2026, 3:05 AM UTC	68	5.56 s	458 ms	1.20 MB	3/3	±10	2,464 -1%	32.4s	Wayback
Aug 31, 2026, 10:18 PM UTC	64	8.12 s	379 ms	1.20 MB	3/3	±6	2,405 -3%	35.4s	Wayback
Aug 27, 2026, 6:58 PM UTC	71	6.18 s	324 ms	1.19 MB	3/3	±16	3,071 +23%	30.1s	Wayback

When

Scores

Perf

LCP

CLS

TBT

Weight

Runs

Spread

Bench

Took

Stack

Filmstrip LAB 🐢 Throttled

Lighthouse Scores LAB 🤖 Simulated

Metrics LAB FIELD

LCP Subparts LAB 🐢 Throttled

LCP LAB 🤖 Simulated vs LCP FIELD

Page weight

By resource type

Third parties 2 entities

Without JavaScript

Page health

Main thread work

Axe violations axe-core 4.13.0, full rule set

Accessibility failures 2 of 27 audits

Best Practices failures 2 of 20 audits

Hygiene

Measurement log

Field history 25 weeks

Runs

Filmstrip LAB Throttled

Lighthouse Scores LAB Simulated

LCP Subparts LAB Throttled

LCP LAB Simulated vs LCP FIELD