anthropic.com

https://www.anthropic.com/

Data from Aug 31, 2026, 9:08 PM UTC 9h old

Overall #1,346 AI #4 Developer Tooling #59 · 1 measurement · since Aug 31, 2026

Stack

Hosted by Cloudflare

Core Web Vitals field data, url-level

Real Chrome users, 28-day window (2026-08-02 → 2026-08-29).

LCP 1.30 s good

INP 91 ms good

CLS 0.030 good

Lighthouse Scores

Performance

no change

Accessibility

no change

Best Practices

no change

SEO

no change

Filmstrip Lighthouse, mobile

How the page drew during the measured load, at 8 points across 3.00 s.

375 ms
750 ms
1.13 s
1.50 s
1.88 s
2.25 s
2.63 s
3.00 s

Without JavaScript

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

10.6% of pixels differ — parts of the page change. A shifted layout counts as difference, so a <noscript> banner alone can account for a large figure.

Lab metrics Lighthouse, mobile

Metric	Current	Previous	Change	Best	Worst
LCP Largest Contentful Paint	2.14 s	—	—	2.14 s	2.14 s
CLS Cumulative Layout Shift	0.052	—	—	0.052	0.052
TBT Total Blocking Time	408 ms	—	—	408 ms	408 ms
FCP First Contentful Paint	2.14 s	—	—	2.14 s	2.14 s
Speed Index	2.49 s	—	—	2.49 s	2.49 s
TTFB Time to First Byte	693 ms	—	—	693 ms	693 ms

LCP Subparts lab observed, unthrottled

The subparts attribute LCP to your server, resource discovery, download, or rendering. Note that the Lab metrics LCP metric shown above is throttled.

element render delay 96 ms

time to first byte 60 ms

Field data Chrome UX Report, url-level

Real Chrome users, 28-day trailing window (2026-08-02 → 2026-08-29).

Metric	p75	Rating	Distribution (good / needs work / poor)
LCP CWV	1.30 s	good	90.1% good
INP CWV Interaction to Next Paint — field only, Lighthouse cannot measure this in a lab run	91 ms	good	94.6% good
CLS CWV	0.030	good	90.3% good
FCP	1.29 s	good	84.2% good
TTFB	814 ms	needs-improvement	74.4% good

Metric

p75

Rating

Distribution (good / needs work / poor)

LCP CWV

1.30 s

good

90.1% good

INP CWV Interaction to Next Paint — field only, Lighthouse cannot measure this in a lab run

91 ms

good

94.6% good

CLS CWV

0.030

good

90.3% good

FCP

1.29 s

good

84.2% good

TTFB

814 ms

needs-improvement

74.4% good

Lab LCP vs Field LCP

Lab 2.14 s

Field p75 1.30 s

The lab LCP is 1.64× the field p75 — real users likely have above-average hardware or network connectivity.

Field history 25 weeks

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

Week ending	LCP	INP	CLS	FCP	TTFB
2026-08-29	1.30 s	91 ms	0.030	1.29 s	814 ms
2026-08-22	1.28 s	91 ms	0.030	1.26 s	780 ms
2026-08-15	1.26 s	90 ms	0.030	1.25 s	757 ms
2026-08-08	1.27 s	89 ms	0.030	1.26 s	741 ms
2026-08-01	1.32 s	88 ms	0.030	1.29 s	742 ms
2026-07-25	1.36 s	94 ms	0.030	1.33 s	756 ms
2026-07-18	1.46 s	124 ms	0.020	1.43 s	872 ms
2026-07-11	1.50 s	154 ms	0.020	1.47 s	909 ms
2026-07-04	1.51 s	150 ms	0.020	1.49 s	897 ms
2026-06-27	1.68 s	145 ms	0.020	1.66 s	888 ms
2026-06-20	1.80 s	126 ms	0.020	1.78 s	798 ms
2026-06-13	2.01 s	97 ms	0.020	1.99 s	712 ms

Week ending

LCP

INP

CLS

FCP

TTFB

2026-08-29

1.30 s

91 ms

0.030

1.29 s

814 ms

2026-08-22

1.28 s

91 ms

0.030

1.26 s

780 ms

2026-08-15

1.26 s

90 ms

0.030

1.25 s

757 ms

2026-08-08

1.27 s

89 ms

0.030

1.26 s

741 ms

2026-08-01

1.32 s

88 ms

0.030

1.29 s

742 ms

2026-07-25

1.36 s

94 ms

0.030

1.33 s

756 ms

2026-07-18

1.46 s

124 ms

0.020

1.43 s

872 ms

2026-07-11

1.50 s

154 ms

0.020

1.47 s

909 ms

2026-07-04

1.51 s

150 ms

0.020

1.49 s

897 ms

2026-06-27

1.68 s

145 ms

0.020

1.66 s

888 ms

2026-06-20

1.80 s

126 ms

0.020

1.78 s

798 ms

2026-06-13

2.01 s

97 ms

0.020

1.99 s

712 ms

Page weight

Metric	Current	Previous	Change	Best	Worst
Page Weight	1.99 MB	—	—	1.99 MB	1.99 MB
Requests	63	—	—	63	63
Third-party Weight	1.88 MB	—	—	1.88 MB	1.88 MB
Third-party CPU	274 ms	—	—	274 ms	274 ms
Unused JS	258 kB	—	—	258 kB	258 kB
Unused CSS	37.7 kB	—	—	37.7 kB	37.7 kB

By resource type

image script font

image 41.2% 817 kB · 28 req
script 34.3% 682 kB · 18 req
font 18.2% 361 kB · 3 req
other 2.3% 44.8 kB · 12 req
document 2.1% 42.2 kB · 1 req
stylesheet 1.9% 38.2 kB · 1 req

Third parties 6 entities

1.88 MB transferred, 274 ms on the main thread.

website-files.com imagefontscript 1.47 MB · 148 ms CPU

Google Tag Manager script 312 kB · 92 ms CPU

cloudfront.net 32.0 kB · 24 ms CPU

hubspotonwebflow.com 26.4 kB · 1 ms CPU

claude.ai 23.8 kB · 5 ms CPU

Page health

Metric	Current	Previous	Change	Best	Worst
Main Thread Work	2.96 s	—	—	2.96 s	2.96 s
Long Tasks	11	—	—	11	11
DOM Elements	1,304	—	—	1,304	1,304
Axe Violations Violating nodes from a full Axe CLI run (more than Lighthouse reports)	7	—	—	7	7
A11y Failures	1	—	—	1	1
A11y Failing Nodes	6	—	—	6	6

Main thread work

script evaluation 1.37 s

other 843 ms

style layout 337 ms

script parse compile 240 ms

paint composite render 115 ms

parse HTML 51 ms

garbage collection 8 ms

Axe violations axe-core 4.13.0, full rule set

7 violating nodes across 2 rules, 1144 passing. This is a standalone Axe CLI run and is stricter than the subset Lighthouse already includes.

serious link-name — Links must have discernible text 6 nodes
moderate landmark-banner-is-top-level — Banner landmark should not be contained in another landmark 1 node

Accessibility failures 1 of 27 audits

link-name — Links do not have a discernible name 6 nodes

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
Aug 31, 2026, 9:08 PM UTC	86	2.14 s	0.052	408 ms	1.99 MB	3/3	±9	2,277 -8%	34.2s

When

Perf

LCP

CLS

TBT

Weight

Runs

Spread

Bench

Took

Aug 31, 2026, 9:08 PM UTC

2.14 s

0.052

408 ms

1.99 MB

3/3

±9

2,277 -8%

34.2s