anthropic.com

https://www.anthropic.com/

Ranks Overall #1,557 Developer Tooling #61 Next.js Showcase #5 AI #3

Data from Oct 16, 2026, 12:18 AM UTC 21h old Measured every 2 days · 21 runs since Aug 31, 2026

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

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 Webflow

Hosted by Cloudflare

Filmstrip LAB Throttled

How the page drew during the measured load, at 8 points across 12.92 s. Compare this filmstrip against another site.

1.44 s
3.23 s
4.85 s
6.46 s
8.08 s
9.69 s
11.31 s
12.92 s

Lighthouse Scores LAB Simulated

Performance

↑ +2 (+2.3%)

Accessibility

no change

Best Practices

↓ -4 (-5.2%)

SEO

no change

Metrics LAB FIELD

Core Web Vitals: passing 3 of 3 assessed from real Chrome users.

Field figures are the p75 across real Chrome users over a 28-day trailing window (2026-09-16 → 2026-10-13), url-level.

Metric	Lab Simulated	Field
LCP CWV Largest Contentful Paint	2.89 s needs work	↓ -124 ms (-4.1%) 2.12 s – 5.81 s	1.39 s good	88.7% 6.6% 4.7%
INP CWV Interaction to Next Paint — field only, no lab run can measure it	n/a	—	91 ms good	92% 5.1% 2.9%
CLS CWV Cumulative Layout Shift	0.015 good	→ no change 0.014 – 0.052	0.010 good	94.2% 4.7% 1.1%
TBT Total Blocking Time	163 ms good	↓ -43 ms (-20.9%) 116 ms – 161.80 s	n/a	—
FCP First Contentful Paint	2.89 s needs work	↑ +26 ms (+0.9%) 2.12 s – 4.76 s	1.37 s good	82.7% 9.4% 7.9%
Speed Index	2.89 s good	↑ +26 ms (+0.9%) 2.36 s – 13.69 s	n/a	—
TTFB Time to First Byte	525 ms good	↓ -22 ms (-4%) 498 ms – 707 ms	802 ms needs work	75% 15.9% 9.2%

Metric

Lab Simulated

Field

Value

Change / range

Trend

p75

Distribution

LCP CWV Largest Contentful Paint

2.89 s needs work

↓ -124 ms (-4.1%) 2.12 s – 5.81 s

1.39 s good

88.7% 6.6% 4.7%

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

n/a

—

91 ms good

92% 5.1% 2.9%

CLS CWV Cumulative Layout Shift

0.015 good

→ no change 0.014 – 0.052

0.010 good

94.2% 4.7% 1.1%

TBT Total Blocking Time

163 ms good

↓ -43 ms (-20.9%) 116 ms – 161.80 s

n/a

—

FCP First Contentful Paint

2.89 s needs work

↑ +26 ms (+0.9%) 2.12 s – 4.76 s

1.37 s good

82.7% 9.4% 7.9%

Speed Index

2.89 s good

↑ +26 ms (+0.9%) 2.36 s – 13.69 s

n/a

—

TTFB Time to First Byte

525 ms good

↓ -22 ms (-4%) 498 ms – 707 ms

802 ms needs work

75% 15.9% 9.2%

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.

element render delay 808 ms

time to first byte 632 ms

LCP LAB Simulated vs LCP FIELD

Lab 2.89 s

Field p75 1.39 s

The lab LCP is 2.08× the field p75 — real users likely have above-average hardware or network connectivity.

Page weight

Metric	Value	Change / range
Page Weight	1.25 MB	↑ +3.2 kB (+0.3%) 1.25 MB – 2.84 MB
Requests	32	→ no change 28 – 63
Third-party Weight	1.18 MB	↑ +3.2 kB (+0.3%) 1.18 MB – 2.79 MB
Third-party CPU	176 ms	↓ -79 ms (-31%) significant 130 ms – 274 ms
Unused JS	257 kB	↓ -2.7 kB (-1.1%) 257 kB – 262 kB
Unused CSS	33.0 kB	↓ -40 B (-0.1%) 32.8 kB – 38.5 kB

Metric

Value

Change / range

Trend

Page Weight

1.25 MB

↑ +3.2 kB (+0.3%) 1.25 MB – 2.84 MB

Requests

→ no change 28 – 63

Third-party Weight

1.18 MB

↑ +3.2 kB (+0.3%) 1.18 MB – 2.79 MB

Third-party CPU

176 ms

↓ -79 ms (-31%) significant 130 ms – 274 ms

Unused JS

257 kB

↓ -2.7 kB (-1.1%) 257 kB – 262 kB

Unused CSS

33.0 kB

↓ -40 B (-0.1%) 32.8 kB – 38.5 kB

By resource type

Type	Share	Size	Requests
script	53.4%	668 kB	15
font	28.9%	361 kB	3
image	8.1%	101 kB	3
document	3.7%	46.1 kB	1
stylesheet	3.1%	39.2 kB	1
other	2.9%	35.8 kB	8
Total		1.25 MB	32

Third parties 6 entities

Entity	Transfer	Size	Main thread Simulated
website-files.com	fontscript	762 kB	79 ms
Google Tag Manager	script	321 kB	69 ms
cloudfront.net		31.1 kB	18 ms
hubspotonwebflow.com		26.8 kB	1 ms
claude.ai		25.4 kB	2 ms
All 6		1.18 MB	176 ms

Entity

Transfer

Size

Main thread Simulated

website-files.com

fontscript

762 kB

79 ms

Google Tag Manager

script

321 kB

69 ms

cloudfront.net

31.1 kB

18 ms

hubspotonwebflow.com

26.8 kB

1 ms

claude.ai

25.4 kB

2 ms

All 6

1.18 MB

176 ms

Without JavaScript

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

12.4% 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.

Page health

Metric	Value	Change / range
Main Thread Work	1.94 s	↓ -733 ms (-27.4%) significant 1.23 s – 180.08 s
Long Tasks	7	↓ -4 (-36.4%) significant 3 – 20
DOM Elements	1,248	→ no change 1,214 – 1,464
Axe Violations Violating nodes from a full Axe CLI run (more than Lighthouse reports)	8	→ no change 7 – 10
A11y Failures	1	→ no change 1 – 1
A11y Failing Nodes	7	→ no change 6 – 7

Metric

Value

Change / range

Trend

Main Thread Work

1.94 s

↓ -733 ms (-27.4%) significant 1.23 s – 180.08 s

Long Tasks

↓ -4 (-36.4%) significant 3 – 20

DOM Elements

1,248

→ no change 1,214 – 1,464

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

→ no change 7 – 10

A11y Failures

→ no change 1 – 1

A11y Failing Nodes

→ no change 6 – 7

Main thread work

Task	Share	Duration Simulated
script evaluation	43%	831 ms
other	26%	497 ms
style layout	16%	311 ms
script parse compile	8%	148 ms
paint composite render	5%	97 ms
parse HTML	2%	33 ms
garbage collection	1%	23 ms
Total		1.94 s

Task

Time

Duration Simulated

script evaluation

43%

831 ms

other

26%

497 ms

style layout

16%

311 ms

script parse compile

148 ms

paint composite render

97 ms

parse HTML

33 ms

garbage collection

23 ms

Total

1.94 s

Axe violations axe-core 4.13.0, full rule set

8 violating nodes across 2 rules, 1218 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 7 nodes

Offending elements (5 of 7)

a[data-cta-text="Announcing Claude Science"]

<a data-cta-text="Announcing Claude Science" data-cta="Home page" data-cta-position="Featured section" href="https://www.anthropic.com/news/claude-science-ai-workbench" class="g_clickable_link w-inli…

a[data-cta-text="Core views on AI safety"]

<a data-cta-text="Core views on AI safety" data-cta="Home page" data-cta-position="Featured section" href="https://www.anthropic.com/news/core-views-on-ai-safety" class="g_clickable_link w-inline-blo…

li:nth-child(3) > .article-list-item.u-detail-m[data-wf--global-article-list-item--variant="featured"] > .g_clickable_link[data-cta-position="Featured section"][data-cta="Home page"]

<a data-cta-text="Anthropic’s Responsible Scaling Policy" data-cta="Home page" data-cta-position="Featured section" href="https://www.anthropic.com/rsp-updates" class="g_clickable_link w-inline-block…

li:nth-child(4) > .article-list-item.u-detail-m[data-wf--global-article-list-item--variant="featured"] > .g_clickable_link[data-cta-position="Featured section"][data-cta="Home page"]

<a data-cta-text="Anthropic Academy: Build and Learn with Claude" data-cta="Home page" data-cta-position="Featured section" href="https://www.anthropic.com/learn" class="g_clickable_link w-inline-blo…

a[data-cta-text="Anthropic’s Economic Index"]

<a data-cta-text="Anthropic’s Economic Index" data-cta="Home page" data-cta-position="Featured section" href="https://www.anthropic.com/economic-index" class="g_clickable_link w-inline-block"></a>

moderate landmark-banner-is-top-level — Banner landmark should not be contained in another landmark 1 node

Offending element

.w-nav

<div data-animation="default" data-collapse="all" data-duration="400" data-easing="ease" data-easing2="ease" role="banner" class="nav_wrap w-variant-bcaa6cc7-fd9c-df6e-98a1-ccc1b40d7604 is-mobile w-n…

Accessibility failures 1 of 27 audits

link-name — Links do not have a discernible name 7 nodes

Best Practices failures 3 of 19 audits

third-party-cookies — Uses third-party cookies 1 item
errors-in-console — Browser errors were logged to the console 5 items
inspector-issues — Issues were logged in the `Issues` panel in Chrome Devtools 2 items

SEO failures 1 of 9 audits

link-text — Links do not have descriptive text 2 items

Hygiene

HTTPS HSTS CSP Clickjacking protection Origin isolation Trusted Types bfcache h3 5 console errors

Measurement log

Field history 25 weeks

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

Week ending	LCP	INP	CLS	FCP	TTFB
2026-10-10	1.37 s	95 ms	0.020	1.35 s	772 ms
2026-10-03	1.36 s	103 ms	0.020	1.34 s	760 ms
2026-09-26	1.35 s	111 ms	0.020	1.34 s	767 ms
2026-09-19	1.34 s	110 ms	0.020	1.33 s	779 ms
2026-09-12	1.35 s	101 ms	0.030	1.33 s	822 ms
2026-09-05	1.33 s	94 ms	0.030	1.31 s	829 ms
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

Week ending

LCP

INP

CLS

FCP

TTFB

2026-10-10

1.37 s

95 ms

0.020

1.35 s

772 ms

2026-10-03

1.36 s

103 ms

0.020

1.34 s

760 ms

2026-09-26

1.35 s

111 ms

0.020

1.34 s

767 ms

2026-09-19

1.34 s

110 ms

0.020

1.33 s

779 ms

2026-09-12

1.35 s

101 ms

0.030

1.33 s

822 ms

2026-09-05

1.33 s

94 ms

0.030

1.31 s

829 ms

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

Runs

Every stored run for this URL, newest first.

When	Perf	LCP	CLS	TBT	Weight	Runs	Spread	Bench	Took	Archive
Oct 16, 2026, 12:18 AM UTC	88	2.89 s	0.015	163 ms	1.25 MB	3/3	±5	3,088 +24%	55.3s	Wayback
Oct 13, 2026, 10:16 PM UTC	86	3.01 s	0.015	206 ms	1.25 MB	3/3	±14	2,433 -2%	63.3s	Wayback
Oct 8, 2026, 11:13 PM UTC	89	2.51 s	0.015	279 ms	1.25 MB	3/3	±13	2,445 -2%	60.8s	Wayback
Oct 6, 2026, 7:02 PM UTC	87	2.70 s	0.014	246 ms	2.84 MB	3/3	±6	3,358 +35%	58.5s	Wayback
Oct 3, 2026, 1:24 PM UTC	71	5.81 s	0.014	116 ms	2.84 MB	3/3	±12	4,433 +78%	54s	Wayback
Sep 30, 2026, 4:02 PM UTC	85	2.67 s	0.014	332 ms	2.83 MB	3/3	±9	2,476 0%	63.1s	Wayback
Sep 28, 2026, 11:03 AM UTC	81	3.33 s	0.014	257 ms	2.41 MB	3/3	±31	2,469 -1%	63.7s	Wayback
Sep 25, 2026, 12:35 AM UTC	84	3.32 s	0.014	127 ms	2.41 MB	3/3	±7	3,058 +23%	59.6s	Wayback
Sep 23, 2026, 12:01 AM UTC	90	2.13 s	0.014	318 ms	2.41 MB	3/3	±7	2,479 0%	63.4s	Wayback
Sep 20, 2026, 11:05 PM UTC	57	2.12 s	0.014	159.30 s	2.21 MB	3/3	±23	2,415 -3%	403s	Wayback
Sep 18, 2026, 1:44 PM UTC	52	2.71 s	0.014	159.63 s	2.21 MB	3/3	±9	2,491 0%	398.3s	Wayback
Sep 16, 2026, 9:25 AM UTC	34	4.76 s	0.014	159.92 s	2.20 MB	3/3	±23	2,442 -2%	398s	Wayback
Sep 14, 2026, 6:09 AM UTC	53	2.66 s	0.014	161.80 s	2.20 MB	3/3	±2	2,534 +2%	404.8s	Wayback
Sep 11, 2026, 11:13 PM UTC	53	2.68 s	0.014	159.35 s	2.20 MB	3/3	±11	2,472 -1%	397.1s	Wayback
Sep 9, 2026, 5:51 PM UTC	52	2.73 s	0.014	159.56 s	2.19 MB	3/3	±19	2,505 +1%	328s	Wayback
Sep 7, 2026, 3:16 PM UTC	47	3.34 s	0.014	159.64 s	2.20 MB	3/3	±16	2,489 0%	327.3s	Wayback
Sep 5, 2026, 12:26 PM UTC	54	2.63 s	0.014	159.01 s	2.20 MB	3/3	±11	2,317 -7%	324.8s	Wayback
Sep 4, 2026, 1:01 AM UTC	55	2.69 s	0.014	157.45 s	2.20 MB	3/3	±5	2,296 -8%	324.3s	Wayback
Sep 2, 2026, 11:12 PM UTC	52	2.79 s	0.014	154.84 s	2.17 MB	3/3	±27	3,003 +21%	315.2s	Wayback
Sep 1, 2026, 10:50 PM UTC	53	2.69 s	0.014	158.97 s	2.17 MB	3/3	±4	2,375 -5%	325.6s	Wayback
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	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 6 entities

Without JavaScript

Page health

Main thread work

Axe violations axe-core 4.13.0, full rule set

Accessibility failures 1 of 27 audits

Best Practices failures 3 of 19 audits

SEO failures 1 of 9 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