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substackcdn.com

https://substackcdn.com· First analyzed 15 Feb 2026· Updated 15 Feb 2026
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substackcdn.com
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Mobile

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Hosting Provider

aws.amazon.com

IP Address

18.165.140.111

Server Location

🇫🇮 Helsinki, Finland

ASN

AS16509

Organization

AWS CloudFront (GLOBAL)

Server

AmazonS3

CDN

CloudFront

Nameservers

ns-98.awsdns-12.com.ns-1445.awsdns-52.org.ns-1936.awsdns-50.co.uk.ns-946.awsdns-54.net.

Performance

Page Speed

0–49
50–89
90–100

Architecture Stack

Monolithic
⚙️ SSR
Substack

SEO Analysis

F17/100
3
5
3
S
substackcdn.comsubstackcdn.com

Error - Substack

No description available for this page.

Title Length16 chars

Recommended: 50-60 chars

Description Length0 chars

Recommended: 120-160 chars

Issues (3)

  • Missing meta description - important for click-through rates
  • Missing H1 tag - every page should have one H1
  • Many images missing alt text (1/1)

Crawlability

Sitemap
robots.txt

2 rules

Allows all crawlers

Sponsored

Sponsored

B

Security Score

71%Good
Static / Informational

HTTPS

WAF

331d

Certificate Details

Type

Domain Validated (DV)

Certificate Authority

Amazon

Key Algorithm

RSA (2048 bit)

Signature

SHA-256 with RSA

TLS Version

TLSv1.3

HTTP Protocol

HTTP/2+H3

Valid From

14.12.2025

Valid Until

12.01.2027

OCSP Stapling

Enabled

Subject Alternative Names (1)

substackcdn.com

SHA-256 Fingerprint

71:44:96:30:87:10:FD:DE:C5:B2:30:F9:E6:26:5E:A9:40:34:45:D8...

Recommendations

Security recommendation preview

HTTP Headers

Developer Console

alt-svc
h3=":443"; ma=86400
content-length
5672
content-type
text/html
date
Sun, 15 Feb 2026 11:12:25 GMT
etag
"bca1df02a0628fc70e30b2da04196f86"
last-modified
Fri, 03 Feb 2023 22:02:04 GMT
Good Warning Issue

Email Infrastructure

Custom Mail Server

Score

0

SPF
DKIM
DMARC

Domain Information

substackcdn.com

Domain Age
3y 10m

Created

12.04.2022

Expires

12.04.2026

Last Updated

09.03.2025

Registrar

Amazon Registrar, Inc.

DNSSEC
Not Enabled

Typography & Readability

-apple-system

73/100
Readability
/30
30/40

17px · LH --

Hierarchy
/20
8/25
WCAG
/25
15/15

Contrast: undefined

Performance
/25
20/20

System fonts

Heading Font

-apple-system

Body Font

-apple-system

Sans17px

Contrast Ratio

--

Reading Comfort

~45 CPL

Needs attention
17px
p

✅ Excellent readability: 17px body text is ideal for all devices.

✅ Excellent performance: System fonts eliminate font loading delays (better LCP).

✅ Clean layout: Consistent center alignment throughout.

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Last analyzed: 15 Feb 2026 at 11:12

Historical Analysis & Change Tracking